Whats the email address for t-mobile users?

I want to send an e-mail to a t-mobile user, so that it shows up as a text message. How do I do it, without asking them to send me an e-mail first? Also how do I check if their number is T-Mobile and not another carrier. I'm pretty sure it is T-Mobile, but it could be Cingular maybe.
Whats the email address for t-mobile users?
Aside from asking the person who their carrier is, there really isn't a definite way to find out who they are with.





As far as the email address, it is their 10-digit phone number @tmomail.net. So, it would look like 1234567890@tmomail.net.
Reply:If it is T-Mobile then the email address would be the phone number @tmomail.net. Guess ask them if it is T-Mobile would be the easiest way to find out.
Reply:you have to text theme or put their # in as the adress