iPad Reader Apps Compared by Jason Perlow of ZDNet

The article describes iBooks (my favorite), Kindle for iPad, the Barnes and Noble eReader, Kobo Reader (from Borders eBooks), the iBis Reader, Stanza, and vBookz.

http://www.zdnet.com/blog/perlow/apple-ipad-showdown-battle-of-the-ereader-apps/13248