Like said before, the biggest pro of using OGG/OGV, is the that the user doesn't need to have the appropriate codec installed 
Software (freeware):
Converter: ffmpeg2theora-0.27
Frontend: GFrontend (ffmpeg2theora) v2007.2 Final
And a small tip because this goes wrong often:
Don't use the playvideo code in 'Before Fade In' a.k.a. "function room_Load()",
use 'After Fade In' a.k.a. "function room_AfterFadeIn()".

Software (freeware):
Converter: ffmpeg2theora-0.27
Frontend: GFrontend (ffmpeg2theora) v2007.2 Final
And a small tip because this goes wrong often:
Don't use the playvideo code in 'Before Fade In' a.k.a. "function room_Load()",
use 'After Fade In' a.k.a. "function room_AfterFadeIn()".
