iPad/Mac: The iPad is a great little drawing tool, especially when combined with a stylus. If you want to improve on the experience even more, Air Stylus is an app that lets you use your iPad and stylus as a drawing tablet for apps on your Mac.
Air Stylus uses the same tech as Air Display, which turns your iPad into a second monitor for your computer. In this case, it turns your iPad into a drawing tablet. You don't get a lot of options for how it works, but you can turn on palm rejection and set up a couple of keyboard shortcuts.
For the most part, Air Stylus works as expected, but there is some lag that will make it tough to use for precision stuff. The lag is comparable to Air Display, so you'll know what to expect if you've used that before. If you're looking for a cheap way to connect your iPad and pressure-sensitive stylus to your computer, Air Stylus does the job.
Air Stylus ($24.99) [iTunes App Store]