If you want to add a feed that shows your Recent Posts in the sidebar, you can use the BuzzBoost feature from FeedBurner (www.feedburner.com). It is very simple.
First, burn your feed at FeedBurner. Then go to your feed's homepage on FeedBurner and click the Publicize tab. From that section select BuzzBoost. (See figure below)
Configure the number of posts to display and the content to appear and then copy the given Javascript code. Add it to your blog using an HTML/Javascript widget. (You can alternatively use the "Use as a widget in" option provided on the BuzzBoost page. This will take you to the "Import Page Element" page of Blogger.)
That's it. View your blog and you will see the recent posts appearing on your sidebar.
