I would never, ever consider developing for the iPhone on a non-Mac OS. There are just too many unknowns when testing or dealing with the framework features that I can imagine running into trouble sooner or later.
I was about to start a thread on this very topic saying how poopy that is! (on the one hand, on the other if I wanna do some iPhone programming then I have a great excuse to get a new laptop! )
Life is not about waiting for the storms to pass. It's about learning how to dance in the rain!" (Just be sure to put your iPhone away in a safe, dry place first.)
I think so too!
I haven't run Mac OS in a virtual box but it might be good enough to learn Xcode and the SDK. My Dell Mini 10 Hackintosh runs Xcode just fine but I only use it when I don't want to carry my MacBook. I agree with the others that you will need to get a Mac to do actual development.