This is a bit of a pain, as transcoding is a very heavy duty task and often an hour's worth of video takes an hour to transcode no matter what software you use (only hardware accelerated encoding would help this). Handbrake is a handy utility that targets exactly this issue ... it was a Mac program but is now available for Linux and Windows as well. It analyses the DVD and guesses which is the main title based on length (you can override if you need to), then allows you to pull that title out and transcode it to something else either in lower bit rates or higher compression formats (eg H264/MP4), and do other stuff like comb filtering, etc. It also allows you to set batches up and let it run over night....
The only failing really is that it does not decrypt protected DVDs, which is annoying (legal issues). You would need something like DVDShrink to do that first. Either you can use this to rip the DVD at the same resolution/size and remove the encryption, dropping it on your HDD then use Handbrake to transcode. Or you can just use DVDShrink to eliminate the extras and shrink it down - note that using DVDShrink allows you to reduce the bit rate (and therefore size), but doesn't allow you change codecs, it must be MPEG2, and so the equivalent bit rate coming out of DVDShrink will not be as good as that coming out of Handbrake if you transcode to a codec like H264.
