For those of you who convert your DVDs to AVIs, there is a cool program that makes short work of it.
Auto Gordian Knot is pretty much a one stop shop and automated the entire process.
http://www.autogk.me.uk/
The only thing not included is a program to "rip" the DVD. But how you do that is between you, Hollywood, and the DMCA 
Seconding the love for AutoGK. A useful side-effect of the way it works is that it dumps the audio, as an MP3, for the video into a folder named agk_tmp in the output folder (it also dumps the original AC3 audio for the purists). This MP3 file already syncs perfectly with the outputted AVI. So, if, like me, you want the original and the riffed version available to watch on your PC, you can do the following:
- Rip the DVD to your HD (*ahem*, obviously only where your local laws allow this).
- Use AutoGK to create an AVI - I usually go for the 2 CDs option to retain some quality. One hint here - go into "Advanced" and choose "CBR MP3", and set it to 128kbps or so, as the variable bitrate can confuse Audacity and Virtualdub later on.
- Go away and do something worthwhile with your time while AutoGK does it's stuff - I personally like to continue building my altar to Cthulu out of discarded chicken bones.
- Come back and you'll have one perfectly-ripped movie.
- Now start up Audacity and load the MP3 file from the agk_tmp folder and the Riff MP3 amd sync them up as in the guide above - I use Audacity's normalise function on the movie soundtrack and punch the volume up on the Riff by about 3db to help Mike's pearls of wisdom come through more clearly. A quick glimpse at the waveforms will let you see particularly noisy bits of soundtrack, and you can drop them a couple of dbs if it helps.
- Export the whole lot as a WAV
- Now start up VirtualDub (
http://www.virtualdub.org/), and load up your AVI. Click Video to "Direct Stream Copy", and then click Audio and "Full Processing Mode", then Audio>WAV. Load up your newly-synced up WAV. Then Click Audio>Compression, and choose MPEG-Layer 3, and 48kbps stero (or higher if you want). Finally, click File>Save AVI, give it an appropriate file name, and leave it to do it's stuff for a few minutes, and you'll have a nicely-synced-up AVI with the riffing, and another without (as if you'd want these films hanging around, I'm sure we've all gone out and bought them because there's no way we'd have Top Gun or Point Break already in our collection, no way, not at all, nosiree...)