is one of the best converters i've tried. zamzar is all well and good but if you have a large file, it'll take a while as it'll need uploading, downloading and uploading again to Bookface.
We support almost all video file types, but
you'll have the best luck with the MP4 format. Here's the complete list:
3g2 (Mobile Video)
3gp (Mobile Video)
3gpp (Mobile Video)
asf (Windows Media Video)
avi (AVI Video)
dat (MPEG Video)
divx (DIVX Video)
dv (DV Video)
f4v (Flash Video)
flv (Flash Video)
m2ts (M2TS Video)
m4v (MPEG-4 Video)
mkv (Matroska Format)
mod (MOD Video)
mov (QuickTime Movie)
mp4 (MPEG-4 Video)
mpe (MPEG Video)
mpeg (MPEG Video)
mpeg4 (MPEG-4 Video)
mpg (MPEG Video)
mts (AVCHD Video)
nsv (Nullsoft Video)
ogm (Ogg Media Format)
ogv (Ogg Video Format)
qt (QuickTime Movie)
tod (TOD Video)
ts (MPEG Transport Stream)
vob (DVD Video)
wmv (Windows Media Video)
The aspect ratio of the video has to be between 9x16 and 16x9, and the video cannot exceed the file size or length that the upload page suggests.
http://www.facebook.com/help/videos/uploading