I like Xmpeg 4.2 for DVD to Divx for converting. If you have a Pentium 4 2Ghz or an AMD Xp 1900+ and above, you can encode faster than realtime. However, make sure you use YUV color instead of RGB. this helps a lot and makes your encoding time much faster.
In case you need a more detailed guide, it can be found here on Tom's Hardware
Link