Free car pool site

I want to start a free web site for finding people to car pool with. I know some exist already, but I recon I can do it better.

You specify your daily trips:
* where from
* where to
* time of day
* estimated time of arrival
* number of spare seats you have
* number of people you currently in the pool

You are presented with a list of other pools that match (closely) your same trip. Once you agree to car pool, the pools are merged to create a single larger pool.

Initially it will be Melbourne Austraia only, but I expect it to grow fairly quickly.