Slider automatico en sidebar (blogger)

Lo que hace exactamente este Slider es mostrar las ultimas entradas publicadas en tu blog de manera automatica y esto lo realizara por medio de nuestro feed, con una paginación bastante agradable.
Se trata de un Slider automatico que funciona a base de jquery, con CSS y un poco de HTML, asi que es muy editable.
Está diseñado a una anchura de 250px de ancho por 340px de alto y es totalmente configurable.

Para colocar este slider en Blogger, entra en la sección de Diseño y agrega un elemento HTML/Javascript, ahí pega esto:

<style type="text/css">
.slider-sidebar{width:250px;height:350px;border:1px solid #ccc;background-color:white;padding:10px;font:normal normal 11px/1.4 Tahoma,Verdana,Arial,Sans-Serif;color:#333;margin:0 auto;position:relative;overflow:hidden;text-align:left}
.slider-sidebar-nav{text-align:center}
.slider-sidebar-nav a{display:inline;background-color:#333; /* paginación visible*/
color:white;padding:4px 8px;line-height:2.6em;margin:0 2px;text-decoration:none}.slider-sidebar-nav a:hover{background-color:#ccc} /* paginación al pasar cursor*/
.slider-sidebar-nav a.current{background-color:#9f9e9e} /* paginación activa*/
.slider-sidebar.loading{background-image:url('data:image/gif;base64,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');background-position:50% 50%;background-repeat:no-repeat}
.slider-sidebar .slider-item{position:absolute;padding:10px;background-color:white;top:0;right:0;bottom:auto;left:0;display:none}
.slider-sidebar .image-wrapper{}
.slider-sidebar .detail-wrapper{}
.slider-sidebar img{display:block;border:none;outline:none;padding:0 0;margin:0 0;-webkit-box-shadow:none;-moz-box-shadow:none;box-shadow:none;max-width:none;max-height:none}
.slider-sidebar h4{font:inherit;font-weight:bold;
font-size:120%; /* tamaño del titulo*/
text-transform:none;
color:#000; /* color del titulo*/
margin:10px 0 0}
.slider-sidebar h4 a{color:inherit;text-decoration:none}
.slider-sidebar h4 a:hover{color:#880505; /* color titulo pasar cursor*/
text-decoration:underline}
.slider-sidebar p{margin:10px 0 0}
</style>
<div id="slider-sidebar" class="slider-sidebar loading"></div>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script type="text/javascript">
(function(a){a.fn.customRotator=function(c){c=a.extend({interval:6000,speed:1000,hoverPause:true,autoHeight:false,crossFade:false,autoSlide:true,hide:function(d){},show:function(d){}},c);var b=true;return this.each(function(){var k=a(this),e=k.children().hide(),d=k.next(),g=null,j=0,f=0;function h(){c.hide(f);d.find(".current").removeClass("current");b=false;if(e.eq(f).next().length){if(!c.crossFade){e.eq(f).fadeOut(c.speed,function(){a(this).next().fadeIn(c.speed,function(){c.show(f);b=true});if(c.autoHeight){k.stop().animate({height:e.eq(f+1).height()},c.speed/2)}f++})}else{e.eq(f).fadeOut(c.speed);e.eq(f).next().fadeIn(c.speed,function(){c.show(f);b=true;f++});if(c.autoHeight){k.stop().animate({height:e.eq(f+1).height()},c.speed/2)}}d.find(".rotator-num a").eq(f+1).addClass("current")}else{if(!c.crossFade){e.eq(f).fadeOut(c.speed,function(){f=0;e.first().fadeIn(c.speed,function(){c.show(f);b=true});if(c.autoHeight){k.stop().animate({height:e.eq(f).height()},c.speed/2)}})}else{e.eq(f).fadeOut(c.speed);e.first().fadeIn(c.speed,function(){c.show(0);b=true;f=0});if(c.autoHeight){k.stop().animate({height:e.eq(0).height()},c.speed/2)}}d.find(".rotator-num a").first().addClass("current")}if(j==0&c.autoSlide){g=setTimeout(h,c.interval)}}if(e.length>1){c.hide(f);e.first().fadeIn(c.speed,function(){c.show(f);b=true});if(c.autoHeight){k.stop().animate({height:e.eq(0).height()},c.speed/2)}if(c.hoverPause&c.autoSlide){k.mouseenter(function(){clearTimeout(g);j=1}).mouseleave(function(){g=setTimeout(h,c.interval);j=0}).trigger("mouseleave")}else{g=(c.autoSlide)?setTimeout(h,c.interval):null}d.find(".rotator-num a").click(function(){if(b){b=false;if(c.autoSlide){clearTimeout(g);g=setTimeout(h,c.interval)}f=a(this).index();a(this).parent().find(".current").removeClass("current");a(this).addClass("current");c.hide(f);e.fadeOut(c.speed).eq(f).fadeIn(c.speed,function(){c.show(f);b=true});if(c.autoHeight){k.stop().animate({height:e.eq(f).height()},c.speed/2)}}return false});d.find(".rotator-advancer a").click(function(){if(b){b=false;var l=this.hash.replace("#",""),i=e.length;if(c.autoSlide){clearTimeout(g);g=setTimeout(h,c.interval)}if(l=="next"){f=(f<i-1)?f+1:0}else{f=(f>0)?f-1:i-1}d.find(".current").removeClass("current");d.find(".rotator-num a").eq(f).addClass("current");c.hide(f);e.fadeOut(c.speed).eq(f).fadeIn(c.speed,function(){c.show(f);b=true});if(c.autoHeight){k.stop().animate({height:e.eq(f).height()},c.speed/2)}}return false})}})}})(jQuery);function makeSlider(a){var c={url:"http://www.amorsevillista.com",numPost:7,newTabLink:false,labelName:null,showDetail:true,summaryLength:60,titleLength:"auto",showThumb:true,thumbWidth:250,squareThumb:true,noThumb:"http://3.bp.blogspot.com/-vpCFysMEZys/UOEhSGjkfnI/AAAAAAAAFwY/h1wuA5kfEhg/s72-c/grey.png",showNav:true,navText:{prev:"<",next:">"},containerId:"slider-sidebar",interval:6000,speed:1000,hoverPause:true,crossFade:false,autoHeight:false,autoSlide:true,onInit:function(){},onHide:function(d){},onShow:function(d){}};for(var b in c){c[b]=(typeof(a[b])!=="undefined")?a[b]:c[b]}$.get(c.url+"/feeds/posts/summary/"+(c.labelName===null?"":"-/"+c.labelName.replace(/\,(\s+)?/g,"/"))+"?alt=json-in-script&max-results="+c.numPost,{},function(s){if(s.feed.entry!==undefined){var r=s.feed.entry,q,p,e,o,h="",d="";for(var m=0,n=r.length;m<n;m++){if(m==r.length){break}q=r[m].title.$t;e=("media$thumbnail" in r[m])?'<img alt="'+q+'" src="'+r[m].media$thumbnail.url.replace(/\/s72\-c/,"/s"+c.thumbWidth+(c.squareThumb?"-c":""))+'" style="width:'+c.thumbWidth+"px;height:"+(c.squareThumb?c.thumbWidth+"px":"auto")+'">':'<img src="'+c.noThumb+'" style="width:'+c.thumbWidth+"px;height:"+(c.squareThumb?c.thumbWidth+"px":"auto")+'">';o=("summary" in r[m]&c.summaryLength>0)?r[m].summary.$t.replace(/<br ?\/?>/ig," ").replace(/<(.*?)>/g,"").replace(/[<>]/g,""):"";o=(c.summaryLength<o.length)?o.substring(0,c.summaryLength)+"…":o;for(var l=0,f=r[m].link.length;l<f;l++){p=(r[m].link[l].rel=="alternate")?r[m].link[l].href:"#"}h+='<div class="slider-item">';h+=(c.showThumb&c.showDetail)?'<div class="image-wrapper">'+e+"</div>":(c.showThumb&!c.showDetail)?'<div class="image-wrapper"><a href="'+p+'" title="'+q+'"'+(c.newTabLink?' target="_blank"':"")+">"+e+"</a></div>":"";h+=(c.showDetail)?'<div class="detail-wrapper"><h4><a title="'+q+'" href="'+p+'"'+(c.newTabLink?' target="_blank"':"")+">"+((c.titleLength=="auto")?q:q.substring(0,c.titleLength)+(q.length>c.titleLength?"…":""))+"</a></h4><p>"+o+"</p></div>":"";h+="</div>";$("#"+c.containerId).css({width:(c.showThumb)?c.thumbWidth+"px":$("#"+c.containerId).css("width"),height:(!c.showDetail&c.squareThumb)?c.thumbWidth+"px":$("#"+c.containerId).css("height")})}d='<div class="slider-sidebar-nav"'+(c.showNav===false?' style="display:none;"':"")+">";d+=(c.showNav===true||c.showNav=="next/prev")?'<span class="rotator-advancer"><a href="#prev">'+c.navText.prev+"</a></span>":"";if(c.showNav===true||c.showNav=="number"){d+='<span class="rotator-num">';for(var g=0;g<c.numPost;g++){d+='<a href="#slide-'+g+'" class="'+(g===0?"current":"")+'">'+(g+1)+"</a>"}d+="</span>"}d+=(c.showNav===true||c.showNav=="next/prev")?'<span class="rotator-advancer"><a href="#next">'+c.navText.next+"</a></span>":"";d+="</div>";$("#"+c.containerId).html(h).after(d);c.onInit();$("#"+c.containerId).removeClass("loading").customRotator({interval:c.interval,speed:c.speed,autoHeight:c.autoHeight,hoverPause:c.hoverPause,crossFade:c.crossFade,autoSlide:c.autoSlide,hide:function(i){c.onHide(i)},show:function(i){c.onShow(i)}})}else{$("#"+c.containerId).removeClass("loading").css({width:"auto",height:"auto"}).html("Error no encontrado!")}},"jsonp")};</script>
<script type="text/javascript">
makeSlider({url:"http://nombre de tu blog.blogspot.com"});
</script>

Ajustes:
Si tienes instalada ya en tu blog la librería jquery, puedes suprimir esta parte del código:

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>

Cambia el nombre de tu blog donde se indica y listo.
En negrita puedes ver algunas variantes para modificar el slider.
Para configurar el número de entradas a mostrar, ( numPost:7) procura no colocar un número alto pues la navegación se saldrá del slider.