Section 'B' : Identifying An Unlocked & Locked Unit:
1) How To Determine Which is Which?

Identifying an iPhone 2G is simple. Just spot the unique silver+black design of the back casing from the following photo:

Determining an officially unlocked iPhone 3G requires a bit more work but is no rocket science. You just have to figure out which country the iPhone is from. Apple maintains an updated list here that you can refer to. The iPhones which do not have a tick under 'Locked to carrier' are the ones you are looking for. You will be shown how to cross reference and verify the part numbers in Section 4 of this guide.

For your reference, the list of officially unlocked iPhone 3Gs are available from the following countries:

2) Quick Trivia

Quick trivia for you. You should have at least visited the official Apple iPhone page which was recommended of you earlier. If not, go now. Ok, so the first thing Apple tells you is "Twice as Fast, Half the Price". Being the typical Malaysian, you must have already done some quick calculations. Half the Price?! US$199 ONLY?!

Well hang on a minute. US$199 sounds like a sweet deal but it doesn't factor in the carrier costs. One main reason why the iPhone 3G is locked in the first place is because it is meant to be bound to a (usually 2 year minimum) network carrier contract. If you add up all the costs of the contract, the iPhone itself as well as the transportation, processing and markup charges, you will end up with the average prices found in the market for an unofficially unlocked iPhone 3G. I'll leave it to you to do the math.

It's in the same quote highlighted in red "here". Anyway, here's the site.

http://support.apple.com/kb/HT1937