I bought an A+ certification book. they talked a lot about cmos in the first chapter (or some more than I would have thought.) CMOS ram that is. anyway here is a link with a java applet :)
http://tech-www.informatik.uni-hamburg.de/applets/cmos/cmosdemo.html
a search for "CMOS RAM" gave me this address
http://www.firmware.com/support/bios/cmosclr.htm
talks about clock chips and using the "debug" dos command to clear cmos ram. talks also some about what cmos ram does (saving settings etc.). and some chips I don't understand.. just one of the links turned up by google :)