When I find a video that I want to have on my 8900. ex; Coach Hines Game Time
or Girugamesh (10 Minute Loop).
If I am taking a video straight from youtube. I'd go to Download Online Videos Save Direct Easily - Savevid.com
and then after when the link is placed and I have clicked 'download Mp4', after downloading that MP4 I would go to Media Convert - free and on line - convert and split sound, ringtones, images, docs -
, and simply press browse, then find the file. It will automatically detect the file version and since it is an MP4 for some odd reason I never read the prompt message, it'll prompt you two windows, and just continue by clicking 'Ok'.
So after you have selected the video from your computer. Just scroll down abit, and then just choose the output file for the video.
Personally I use .3GP for videos on my 8900, but I don't know any other ones that work. I've tried MP4 and no use, so I just ended up using .3GP.
If you want you can also use this process for downloading songs, which is safer then LimeWire/Bearshare/etc.. But it might take abit longer to acquire your desire!