You may look here:
http://www.aoamedia.com/videoconverter.htm or
http://www.riverpast.com/en/support/tut ... at/avi.php
But from my experience: Depending on the format the files are on the VCD, there is a lot of manual work ... not sure if it is worth the time (like the above poster also mentioned).
I ran in the same problem with DVDs - there it might be somewhat easier, as the single songs can be extracted one by one and then converted to the file format of your choice - but still a lot of work.