Passcode Unlock. Urgent help please!!!

[kingofburroughs]

Friend of mine asked if I could unlock his iphone for him. (Broke his g1 and wanted an iphone as a substitute.) Now he gave me his T-Mobile sim card and the iphone but when I connect the iphone through my usb cord it rises an error message saying it's locked with a passcode and must be unlocked on the phone first. The problem is, is that the phone is stuck with the screen that shows the usb cord an upward arrow and an itunes logo. So I cannot enter the passcode it's requiring. How should I go about getting to the main springboard screen?

Thank you in advance for the help.

[battlecrushr]

put the sim card in another phone and then remove the sim lock

[kingofburroughs]

if I put that sim into MY unlocked iphone, how would I go about removing the SIM lock?

I used my friend's sim card into my old sidekick 3 and went into the "Sim Center" here I found out about the Sim Passcode, or "Sim Card Lock" as it's called in the sidekick. The only problem is, is that it asks for the SIM PIN to enable the lock, not how to disable, nor do I know the SIM PIN..