Great blog post about the implementation of an iPad pilot program in a 5th grade classroom. The focus of the article is on student learning rather than technical configuration.
This blog post lists several apps to use for mobile grading and keeping a grade book on an iPad. It is important to note that some Student Information Systems - such as Pearson's PowerSchool - have developed apps that integrate directly with the computer-based grade books.
iPad Academy is a great blog, and to celebrate it's 50,000 visitors, they posted this list of "70+ starter apps". It's a great resource for getting started with iPads.