I bought an iPhone in the US without a contract, which requires paying full price. It is unfortunately still locked to AT&T, which means I cannot use it in Singapore. However, if I unlock it, I can use it on any network. Unlocking for personal use in the USA is not illegal, according to the exemption given to the DCMA. Since I live in Singapore, it is not clear what law applies. Anyway, if I am doing for personal use and have already paid Apple the full price of the phone, I can do what I want.
I asked a friend who has experience with this. The process involves installing Cydia.
Anyway, thanks to my friend, my iPhone now works beautifully in Singapore. I am able to use any SIM card I like. I must say the audio quality is better than any phone I have used previously. However, I cannot update my firmware without going through the unlocking process again. I can still install apps–in fact I just installed Skype.
One annoying thing about Apple’s phone keyboard is that all phone numbers are displayed in (3)-3-4 US format. Here in Singapore, the number are in 4-4 format, and Apple’s reformatting throws me off. Strangely, a simple option to display numbers in non-US format is not available in any of the menus I have seen.