Adobe just released an SDK so developers can build iPad apps that control Photoshop on your computer. And they announced three of their own!
Easel - Paint on your iPad, beam it to Photoshop.
Nav - Navigate open files and put your tools pallets on your iPad.
Color Lava - Mix up color swatches onyour iPad, beam ‘em to Photoshop.
Each runs on your iPad and interacts with Photoshop over WiFi.
p.s. Adobe, iPad-based Lightroom editing, plz! KTHXBAI!