...and because this is good stuff to know. This is a pamphlet that's been distributed in Australia to couples who plan to move in together. It's probably the most complete and helpful information I've found, and I agree with almost everything they say on the subject.
http://www.facsia.gov.au/internet/facsinternet.nsf/vIA/families-keys_to_living_together/$file/keys_premarriage.pdf