If you want a laptop/netbook, buy one. Don't bastardize your iPad 2 by bolting a keyboard/case on it that tries to make it a laptop.
But if you must, Menotek makes a decent one. The Menotek iPad 2 Bluetooth keyboard and case has a waterproof keyboard that works with your iPad and your iPhone 4. In addition when fitted to the iPad 2 and closed it resembles a leather bound netbook. Expect to see this on Amazon on April 15th for under $80.