I found groupcarpool.com much easier to use with a simple user interface. And rydeful.com is more detailed, but it is probably better at helping you optimize drivers and logistics.
I setup an account with Odyssey PTG with one example driver here:
It is free for up to 50 participants. If we all setup carpools on the same site then there is probably optimization that can happen easily just by picking the pickup locations nearest to you and/or adding yourself as a driver for others in your neighborhood.
For more info on forming carpools, read this article: