Followup - I finally got this to work.
Long story short - I bought an ATT galaxy S3 and was only able to get EDGE speeds initially. I did some reading over at xda-forums and was able to flashed it over to Tmobile and have been able to get 3G/4G since.
Hey guys, I just signed up for this plan and am using an unlocked ATT Galaxy S 3 but am only getting EDGE speeds. Any ideas on how to get this to work with the 3G/4G? My phone service is fine. Thanks for any help anyone can provide me!