ColorSplash - Once you've got your pics loaded, use color splash to auto-convert them to black and white and daub color onto the areas you want. Pretty slick. Great tutorial.
I-Prompt Pro - Remember the free TelePrompTer @shareski used in his 2010 K-12 Online pre-conference keynote? This is the app. Spring for the $80 remote and you're really in business.
web2vga - Let's you hook your iPad up to an LCD projector or TV and take your audience to your favorite websites. All you need is the Apple Composite A/V cable.
Cam for iPad - Load this puppy on both devices and transmit streaming video and audio from your iPhone to your iPad. Baby monitor in a pinch? I know which device will run out of juice first.