Billmonk

A shared expense and stuff tracking service for friends.

Features:

Easily track shared expenses (shared bills)
Easily settle debts through obopay
Track other items that you have and have lent out (books, movies, etc.)
Catalog your items (export into myspace profile) and browse through cataloged items of your freinds
Export list of your friends from Facebook into your Billmonk account
Freely log expenses and shared bills to Billmonk via sms
Flexible notification system (you choose settings on which actions should Billmonk notify you)