Stanza and other iPod reading apps.

 Stanza reads epub formats, and can opened books purchased at B&N and other some sites by reentering credit card information (once per book), plus it has in app links to some stores, and free book sites.. Kindle only reads .azi/.mobi and in general I prefer cross-platform formats. I found the B&N app terrible, and I'd much rather jump through the re-enter payment hoop to store and read books on Stanza.

The mac iBook app itself runs with excruciating slow pages turns on my previous gen iPod Touch (which is, btw, the worst named of any Apple product).