[blackhawk556]

I'm going to unlock either a samsung focus or LG quantum and give it to my sister (she's on tmobile). Are the codes one time use then?

Anyone know the best place to get the code? while you're here, best place to also get MMS & data settings for these phones?

[Winning Guy]

If you bought it from AT&T, and you've owned them over six months, just call AT&T and tell them you want to unlock those phones. I've unlocked 2 Samsung Focuses, an HTC Titan, and a ton of older phones just by calling.

I think the only exception to this is the iPhone.

And yes, you only use the unlock code once. They'll ask you for the IMEI number of the phone you want to unlock. Once it's unlocked, it's permanent.

[Guzzler3]

I think the only exception to this is the iPhone.

If the iPhone is paid off (you've made it past the initial contract, or paid full price for it), they will unlock the iPhone now. You just need to call AT&T (or your current carrier), give them the requested info, and wait. You will eventually get an email saying to to connect to iTunes and do an update (or was it a sync, I can't remember). iTunes will display a message that your iPhone is now unlocked. Then you are good to go to use another carrier. (Been there, done this).

The carrier has to send the unlock request to Apple which is why it can take awhile to get the email.

[drugtab]

If you need to unlock your Samsung Focus you can get it from www.unlock-zone.com/samsung-focus/rs16wp9/ . this site is one of the trustworthy source to get accurate unlock codes at low cost. I am searching similar trustworthy source for LG Quantum, But couldn't find any one. I will get back to you soon if i find any.
And yes the unlock codes are one time use. Every phone has an unique unlock codes based upon its IMEI number. Once a phone is unlocked using an unlock code, It can be then used with any international GSM SIM card.