Widgetbox offer the easiest widget maker I've tried so far - it's free to use the blog widget maker and the wizards easily walk you through the process of creating a widget for your blog that you can put on places like myspace, facebook, bebo and many other social networks.
To read my simple guide to creating a widget - visit :
http://www.widgetbox.comyou can basically make a bliget widget out of any RSS feed you'd normally put in a reader - but you want it on your website to share with friends.