I know there are emulators, but is this good enough? If someone is serious about iPhone development, do they absolutely need an iPhone?
Just my personal opinion: if you're serious it means that you're committed to quality of your product. If you're committed to quality there is no way to deliver a product without actually launching it on the target platform :)
As noted in other posts you'll have tough time testing the multi-touch screen and other aspects of the hardware on your emulator.