Yes it’s true, the Nexus S will land in “All Best Buy and Best Buy Mobile Stores Dec. 16 … at 8 a.m. Eastern time,” but that’s unlocked only. It doesn’t mean you can buy the device on T-Mobile contract at all BB locations.
Lucky for you, Best Buy has taken it upon themselves to create a list of all Best Buy locations where you can indeed purchase a Nexus S on T-Mobile contract. To view the list in it’s entirety you can visit this Best Buy Mobile Nexus S locations .PDF, and see if any of your local Best Buy made the list. Hopefully you’ll have more luck than I did, as neither mid-Michigan Best Buy locations did.