Do you have an AT&T Tilt with Windows Mobile 6.1 on it? Are you trying to play your 3GP files on it? Are you frustrated by the million or so posts on the web about how to make it work properly? Do you feel you should just be able to download and install a codec or something to make it just WORK? Well, here's the answer:
Download and install a special version of TCPMP made just for the Tilt. Once you install it, you can use TCPMP to play your 3GP (and a myriad of other files) videos!
That's it....have fun!