I bought a Galaxy s2 in October. Great phone, but I've found I use my tablet for data and don't use the phone enough to justify it's cost. If I end my contract and pay the ETF, will AT&T automatically unlock my phone? I'd like to sell the phone to recoup some of what I paid for it and the ETF.
You don't need them to do anything. With a GSM phone you remove your SIM card and then sell it. Who ever buys it will need to run it on At&t since the phone only has the radios for At&t. Just remember to do a factory reset to delete all your data before selling it.
Do a Google search for cell phone unlocking. It is cheap and fast, under $5. No AT&T will not unlock your phone
If your account is in good standing you can just call them and they will give you the code, this is not an iPhone and they have ALWAYS done this for Blackberry's and Windows Mobile. I recently did this for someone with the OG AT&T GSII with no issue over the phone. Just make sure you have a SIM from another carrier or you won't get access to the GUI pop up to enter it. I have also seen this as an option online by some phones pic's in account management.
Why not unlock it yourself? I did. It's free too. Download the "Galaxy S Unlock" app authored by "Helroz" from the Android Market. Worked like a charm for me. [GUIDE] AT&T Galaxy S II Unlock Steps - xda-developers
Not sure if the OP is actually wanting his phone unlocked or does he just mean that he wants to sell it and doesn't know if they will let him?
So, if I understand, I don't need to unlock the phone to sell it. I just need to remove the SIM card and I can sell it to anyone who wants to use it with AT&T's network. Is this right?
Yes you correct, all you need to do is take out the sim card and you are good to go. As simple as that. Good luck selling your phone!!