Help with video subtitles

[TabulaRasa]

I am watching foreign films and tv shows and I want to add subtitles to them, english ones of course. I want to know...is there a program for that or do I have to load the video in something like windows movie maker and do it frame by frame adding the text? If so, that will take forever!

HELP!!!!! 🙂

Muchas Gracias.