I've been thinking for a while about the unique challenges of testing mobile, touch-based devices. I'm crafting this post entirely on my iPhone, and working around the UI designed for keyboard/mouse-based computers. [I ended up having to type it in an email, and tried the email-to-post feature, but now I've resorted to copy/pasting text from a bounced mail message to a browser window on my desktop machine.]
As a Mac and iPhone software tester, I'm itching to get my hands on an iPad as soon as possible. I told one of our engineers today that I think it's essential for testers to literally get their hands on these devices. I did some iPhone testing before I owned one, and did a decent job of finding bugs on borrowed devices and the simulator. But once I got an iPhone and began to use it day-to-day, I discovered all sorts of new user scenarios. Airplanes, reading in bed, Seattle weather, ... I expect the iPad will not be just a giant iPhone, but have a whole new set of interactions. I look forward to the discoveries. And who can turn down a shiny new toy?
Some other people have written much more eloquently on why it's not just a giant iPhone: