I think this might answer a few million of your questions.

Take a look at the iPad Education Dreams group on facebook.  There are some great links and ideas and some that are not very helpful.  The one I found last night looks to be amazing.  It is from the edtechteacher blog and this post is about using the iPad, no surprises there.  I like the way it will help you narrow down what you are looking for based upon the task you are attempting to accomplish.  Take a look at the post and see where it will lead you.