I have just got the new HTC Touch HD and it runs on windows mobile. I have been trying to put videos on but they just do not show up on the device. I think it is something to do with the format that the videos are in. They are at the present in mp4 what do i need to do to get them to play on my device??? Do i need to change the format or is there a program i can install on my device so i can play them. (FREE)

Thanks