I had the same problem, and using divx / xvid will reduce the image size.
There is some reduction in the quality, with parts the same colour losing definition, but it is getting better with the DivX 5 codec. If you know how long the video lasts for as well, you can use the bitcalucator by Terry Savon (I think - google'll find it - just search for bitcalc.exe) to calculate the number of kb/second - and this can vary dependant on the audio quality as well - although 128kbps isn't too bad for it - not really noticeable unless you are using it through a decent stereo.
Up to 800Mb CD's (take off a bit if you want to make it into a VCD - Nero isn't half bad at that) also will help in keeping the quality high.
The other solution is worth about £200 and is called a DVD Writer....