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!
Tabbt - Tabbt takes the hassle out of handling money among friends.
Memodude - Memodude keeps track of who you lent to, reduces your receivables and gets rid of bad payers.
WieBetaaltWat - With WieBetaaltWat you can manage a list with your shared expenses.
Kittysplit - The easiest way of sharing costs with a group of friends
Tricount - Manage and share expenses with friends