You can use the dd tool. It's not newbie-friendly, but very usefull.
Mount the partitions you want to copy read-only and run something like: dd if=/dev/hda6 of=/mounted/folder or dd if=/dev/hd[x][y] | gzip > /path/to/image.gz
Explore and test the command extensively before you run this inside your working system. It's very powerful onces you get the hang of it.
Otherwise try: http://mkcdrec.ota.be/project/index.html