rip the .VOB file from the DVD usind DVDripper.. and then use virtualdubMOD to convert them into .avi ..
www.virtualdubmod.sourceforge.net
Alternatively, u can use Imtoo DVD Ripper [
www.imtoo.com/dvd-ripper.html]
which gives u the options of converting a DVD to n no. of CDs as per ur req. but unfortunately is not free. On the other hand VirtualdubMOD is free but u hv to experiment a little to get ur desired compression.