AVIAddXSubs
AVIAddXSubs is a simple free program to incorporate subtitles (XSUB) from .srt (ANSI text, up to 8 srt) or idx/sub (containing up to 8 subtitles) quickly and easily to your avi files containing DivX/XVid video streams.
http://www.calcitapp.com/AVIAddXSubs.php