Bluefire have just announced their new app for iPhone & iPad. It boasts support for Adobe DE DRM as well as formatting options equal to Stanza. You can even download or buy ebooks from inside the app.
Normally I'd give an opinion of the app but lately I've been having the strangest problem with my iPod Touch. I can't download apps. But I have been following the tweets of a couple people who have it, and they are impressed.
The following are a couple of tweets that I tried to embed. Unfortunately, they didn't come through the RSS feed. I won't embed them again.