I see a lot of people that sign up for GoodReads and then add their 'Currently Reading' shelf as a widget. Is what I did for a while, but I've turned it into a button as scripts are tending to choke my blog's loading times.
I've been looking for one as well-- I'm a Goodreads member, so I thought that could do it, but it doesn't seem to want to work with my Wordpress page (or maybe I'm just doing it incorrectly, which is completely possible).
GoodReads eh? I'll have to check it out. Thanks!
Goodreads is amazing, it's a pain to find the widget when your looking though.
Add all the books you are reading/want to read - etc.
Click on the top "My Books" link and you will see a tiny widget link. You can choose which "shelf" to show. I have the widget on my site right now, it's quite awesome.
Goodreads.com is also great for the community itself.