I really don't think it matters what format their in, t-mobile along with most cell phone service providers, filter their incomming and outgoing mail through their mail servers. I've been told that this mail cannot be retrieved, meaning that someone at t-mobile could be reading you mail but...... Ever once in a while I was able to get one or two to go through but that didn't last. Although I'm not sure about the mail system on a sidekick if it goes through t-mobile then you most likely are going to get an attachment dropped error.

im trying to hook my friend up with some free ringtoens for his sidekick 2. what format do they need to be? ive tried mp3, wma and wmv, the wmv said play under it, but they somethng about how it couldnt play. what format does it need to be.