The other thing you may want to know is that today there was a nation wide outage with the T-Mobile system that affected data changes to accounts. If you do have the data plan it may take upto 72 hours to fully provision. you should go to T-Mobile.com and register and set up your email. Tomorrow reset your phone by turing the wireless off or removing the battery, then go online and send the service books to your phone. Hopefully the delay will have gone though by then.
I have a Pearl through Cingular with out a data plan. Sometimes it will say Cingular under the time, and sometimes it will say "data connection refused". I dont know why, but it likes to switch back and forth.