Vernier offers a host of products to support physics instruction, and for $2.99 there is now an app. Students can perform hands-on experiments and collect real-time data through the iPad.
"CCL4s provides an interface for entering observation data as well as access to all the Content Standards for Mathematics K-12 and the ISTE NETS.S. The collected observation data can be shared via email or with our unique built-in instant meeting. The graphs are very interactive and allow observers to merge different observations to compare and contrast different teachers or the same teacher over time. Using the Timeline feature, observers can track the observed Look-fors through time."
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.