Apple has published iOS 7 user guides on the iBookstore for iPad and iPod touch users. Both provide useful information on a variety of subjects, from navigating Mail, Maps and Newsstand to sorting out any problems.
The iPad and iPod Touch user guides are free to download and can be found here and here. Apple has offered user guides on the iBookstore since its conception in 2010 and is expected to follow-up with an iOS 7 guide book for iPhone users in the near future.
Apple released iOS 7 yesterday but the operating system update only brings all of its features to users with the fourth-generation iPad, the first-generation iPod Touch and iPhone and the original iPad mini.