http://apartments.about.com/od/roommates/ - about.com has links to articles such as to roommate or not, and the roommate agreement.
http://www.roommates.com/ - Roommate matching service (seems mostly free)
http://www.thesublet.com/ - Apartment listings, roommate listings (requires registration to get contact information)
http://www.apartments.com/ - Search nationally for apartments
http://www.roomiematch.com/- Find a roommate based on your personality
http://gothic.apocyber.net/ - Find Pagan or Gothic roommates in the classifieds section.
http://www.rainbowroommates.com/ - Gay and Lesbian roommates
http://craigslist.org/ - An awesome page with Apt resources, job, community, and more.
http://www.livejournal.com/community/nyc_real_estate/ - another more active NYC roommate community, hey let's get some of those guys over here!
http://www.gilderlehrman.org/historians/fellows_housing.doc- Listing of cheap places to live.