InfoCentral was a piece of software I wrote for my church about two years ago. They had been tracking congregational information (people, families, group attendance, etc.) using multiple AppleWorks databases (which are really just flat spreadsheets anyway), and it was getting out of hand. InfoCentral was meant to get everything in the same location and have everybody updating the same data source.
I open-sourced the software about a year ago, and another guy was sharp enough to grab the www.infocentral.org domain name when it expired one day. All the information (as well as a working demo) of the software is available there. It’s a PHP/MySQL-based Web application.
As far I know, InfoCentral is in use in a handful of churches from coast-to-coast. I have more plans for it, but sadly, open-sourcing hasn’t resulted in an appreciable amount of development support. A few people have sent code, but mostly everyone is kind of standing around wait for someone else (usually me) to do something. My biggest concern right now is documentation — the system has very little, and I think that’s a roadblock to adoption.