HDcam is an iPad app that lets you use an iPhone as a wireless camera. It's similar to the Camera A/Camera B apps we've covered before, but has received a nice update for iOS 4.
The app is now faster, produces better quality pictures, and will connect your iPhone to your iPad automatically. It is available in the iTunes store now, but heads up: It'll cost you $2 and is only compatible with an iPhone 3GS or an iPhone 4. [iTunes]