Converting movie files to .3gp or .mp4 for cell phones

[sleepy180]

Hi i have a few questions on converting regular .avi .mpeg .wmv files into .3gp or .mp4 for cell phones and the like.

I have used already at least 3-4 different converters trying to convert them to those formats and they all work, the size gets reduced, the quality and the sound all look good (240x320 for my cell phone). But always, in all of the programs, the sound becomes out of sync. I am only converting music video's at the moment onto my samsung t809 cell phone but the music always always always gets out of sync by 1-2 seconds. Every type of file i try to convert, every program i use, and it sucks. I am using the same fps and bitrate and everything that SHOULD be correct for my phone. 15fps. Im just lost now.

Now ive only ever tried to change the format to .3gp because i havnt found a good .mp4 converter. Does anyone have any thoughts on my out of sync issues or does anyone have a tested and working converter to change format into .mp4. THanks for all the help and sorry if i sound like a newb.

[sleepy180]

anyone please?