Kopa Housemate Finder - Find furnished apartments and housemates for 1+ months
RentHoop - Tinder for finding roommates
PadMapper - A free tool to help you find an apartment or sublet to rent.
Splitwise - Splitwise is a free tool for friends and roommates to track bills and other shared expenses, so that everyone gets paid back. On the web, iPhone, and Android!
Campus Cribz - College student rentals and roommate matching
Roomr - Discover great people to live with