I wish this question could be made a sticky somewhere… this is the 4th time the question has been asked in a week.
well; you can develop without a mac - but, you need a mac to do the last compile/signing process if you want to have it on a device or upload it to the store.. we currently use mac for developing; but, not the iphone SDK (we build a native mac osx version).. but we could also use windows and/or linux. the end result tho; we MUST use the mac to build for the device and app store.