If an iPhone 6 was purchased via ATT with a 2 year contract, is it locked to ATT for the term before it can be GSM unlocked? Is there an article that shows this information? Thanks.
Yes it is locked to AT&T for the term of the contract. I'd contact AT&T and ask about this. I don't know where they'd have this information published, if it is published at all.
A lot of us are having success getting on contract ATT phones unlocked. Read this thread here: http://forums.macrumors.com/showthread.php?t=1837666
Yes it is locked till the contract term is up. You can try submitting an unlock request to have them unlock it early. Or you could buy an unlock from a 3rd party seller for around $75.
Try the unlock request form on the AT&T website They just unlocked my 6+ a few days ago. I've bren trying a few months but it's worth a shot.