The newest mobile Moodle app to hit the scene, mPage, is free, works for teachers and students and works on iPhone and iPod touch. More information is available at http://moodle.org/mod/forum/discuss.php?d=104599.
More details as we find them. Or post your own in the comments.
Download the app from http://itunes.apple.com/us/app/mpage/id369809342?mt=8