iPlan Lessons is an iPad/iPhone app ($9.99) I just had to try out thanks to Vicki Windman's review I read on T & L. While the price is a bit steep for an app it offers up a great solution for teachers to keep and interact w/ their lessons all in once place. A teacher can keep track of their students, integrate their lessons w/ a calendar and add lessons w/ categories and resources. There is even an area for reports (not sure if they are automatically generated) which is nice.
I highly recommend checking out iPlan Lessons by clicking here!!