The traditional way for housemates to stay in-sync regarding bills, chores and social activities is a notepad, pen and centrally-positioned, fridge-shaped object. If you're looking for a more technological method, then the upcoming Fairshare app, developed locally in Melbourne, might be exactly what you need.
According to its developers, Fairshare was developed over a ten-month period in an East Melbourne sharehouse, so you don't have to worry about the app featuring US-centric features or terminology... and that it was tested on the front lines of sharehouse living (a dangerous battlefield if there ever was one).
As you can see in the video, chores are assigned point values and when completed, can be dismissed with a simple swipe. A nice feature is a community feed for your house, so flatmates can post social events, gauge interest and seek comments.
Unfortunately, the app isn't available just yet -- you'll have to wait until 21 February, after which you can grab it from the App Store and Google Play. No word on pricing, though my guess is it won't cost more than a few dollars.
Fairshare [Official site]