i do like this:
virtualdub/ subtitler/ ssa files and avi's files of course!
put subtitler in your virtualdub's plug in
1) open virtualdub
2)video, full processing mode
3)open your avi file
4)audio, direct stream copy
5)video, filter, add, subtitler, your ssa file, preview, ok
6)video, compression, choose your codec (xvid or divx) ok
wait a little and you obtain an avi sub!
http://fs06u.sendspace.com/processupload.html = subtitler