The last of the Goo Balls didn't know that they were on a pad, or that they were extremely tactile. World of Goo is now available on the iPad! Get it from the App Store here for just $9.99.
GooTool for iPad is also pretty much done, I'm just looking for someone with a jailbroken iPad and some technical-savvy to help test it out before I release it. Let me know if you can help!