Up until recently, those who've been wanting to own an iPhone in the Philippines have been forced to buy their unit abroad, have it unlocked, and risk bricking it everytime they use it (ok, maybe a bit over exaggerating with this line, but you know what I mean). They might have the newest Apple toy on the block, but they won't have the full functionality of the fully-working official deal.
Lately however, one of the biggest networks in the country have decided to officially bring the iPhone to the Philippines. Globe has recently announced and started selling the iPhone locally. Lucky you if you happen to subscribe to one of the higher plans that globe provides, or if you intend to get a line and stick yourself with the minimum 2 years at those rates, but if you're thinking of just buying the phone outright, as a prepaid kit, and keep your old prepaid number, get ready to shell out at least Php 37,599 (for the 8 gig model) or Php 43,799 (for the 16 gig).