Welcome to the forums! A simple search could have answered the Q as it has been asked over and over again....
BUT
Log into the My T-mobile website and then select "Setup BlackBerry Email'
Then
Edit the account you wish to remove the signature from and remove the signature or change it and save
Walla, it's gone
![Smiley](http://www.blackberryforums.com/images/smilies/icon_smile.gif)