Klokwerk linked to the wonderful DivXLand Media Subtitler in a thread I made about subtitling things and it's amazing. There's a video preview window, and a box to enter text in and when you want the subtitle to appear, while the video is playing, you hit the "apply" button and it writes the timecode for that subtitle. Then you can export it in any number of formats. The only problem I ran into was that since the video window is Windows Media Player, it wouldn't play MPEG2 for me properly, so I just converted what I was working with to a low-quality XviD file to work with and the subtitles I created sync up perfectly.