Now we learn shows the recent blog post in the sidebar using RSS FEED. How very easily. The steps is :

Login to blogger dashboard Layout -> Page Element -> Add a Page Element -> Feed

1. Using default blogger Feed
http://blogname.blogspot.com/feeds/post/default

2. Using Feedburner Feed
http://feeds.feedburner.com/FeedPostName

Do not forget to change the RED color with a name / name of the feed you post :)

source : http://www.o-om.com/2008/03/membuat-recent-post-via-feed.html