i really need help getting this on at&t..

[tzx3]

hello,
i have seen that people have the HD2 on at&t, but i havent found how to get it on at&t myself.
i called at&t and they said that the unlock code couldnt be found. i have searched through ppcgeeks, xda, google, and a few other places, but the only thing i came up with was buying a code from a website. i suppose i could do that, but i need to know before i buy one, if the sim can be unlocked via other methods?

thank you