Try
ffmpegX. It's a bit of a pain to install and use, but it's a very, very versatile and powerful video converter. You can use it to convert vobs from a DVD into a VCD, optionally selecting a subtitle track to use.
Keep in mind that if you're using VCD, you can't have subtitles the way a DVD does. The subtitles will need to be burned onto the video track, so you won't be able to turn them off or have multiple subtitle languages.
Also, of course, the video quality will suck with VCD. VCDs use MPEG1 video at pretty low resolutions, so expect quality MUCH worse than DVD.
If your DVD player support MPEG4/Divx, you may want to burn it that format, which will look a helluva lot better than a VCD. To find out if your DVD player supports this, look it up at
http://www.videohelp.com/.