FYI Tmobile do NOT own SideK!ck! I know many people thought Tmobile owns it. In reality, Tmobile became exclusive wireless carrier provider contract with Danger, Inc. As you see, Danger, Inc is the one who owns Sidek!ck, not Tmobile. Don't believe me? Go ahead check
www.danger.com There is info in there. Same principle with Blackberry. These two companies are independent and have contracts with wireless carrier. Any other wireless devices usually owns by Tmobile, or any wireless carriers. But for Tmobile, you could move simcard to any wireless device with exception of Blackberry and Sidek!ck! What does that means? It means that you can NOT use Sim card from Sidek!ck to another Tmobile device! But if you have Tmobile device like a nokia phone and decide to transfer simcard to LG phone, can do that without contact Tmobile. That is because Tmobile don't have any contracts with these phone makers, they just bought it and sold to you.
This is clarification for you that Tmobile do NOT own SideK!ck, but just exclusive contractor as wireless provider service PERIOD.