I was in a hurry to get to sleep last night so I didn't talk much about this aside from posting a screenshot, but yesterday I was able to get my iTelephone unlocked and was blown away by how easy and fast it was.
I got my iPhone 3G from Optus which meant it was tied to their SIM card in Australia; travelling back to my other "home" in Singapore meant the device just became a fatter, glorified iPod Touch. Calling Optus from here though all I had to do was prove my ID and ask for it to be unlocked for it to be activated on their end. Optus claimed they usually need 10-15 business days to push through an unlock but because I was overseas already they "pushed it through" faster and promised it'd be done in 24 hours. And to their credit, it was!
Once I had backed up my iPhone in iTunes I did a complete restore, during which time I was told my carrier had some new settings to transfer which I presume changed the IMEI number to a carrier-neutral setting. When I popped out my Optus SIM and pushed in the SingTel Mobile 3G card I had from my Centro with the data plan, it worked beautifully.
I've had mobile phones for many years but this is the first time I've had to deal with the issue of "locked" phones which is more of an American phone company thing. The iPhone is an American designed phone so I guess this makes sense.
Anyway I'm super pleased I was able to get Apple and Optus to unlock it without question even though my 12 month contract hasn't expired so I can use my iTelephone here. Singapore has brilliant phone coverage, I've been walking around all morning with it and have had full signal strength for 3G the entire time. Back in Adelaide I only get a decent 3G signal in the CBD. The iTelephone was built for places like Singapore!