Will you be playing these movies on a settop dvdplayer? If you are just playing them on you computer you can use mplayer to view subtitles with them. You can get subtitles from
http://www.opensubtitles.org. For your purposes I would try to get the SRT format. Rename that .srt file the EXACT name as your movie file and put them in the same directory. Then, when you watch with mplayer your subs will appear too. Be careful though, you have to be mindful of the framerate of your video when getting subs from elsewhere. If not, your subs may be out of sync.