c3p0 is now maintained on github.
You can still find releases at sourceforge.
Documentation is available as part of every distribution, as well as on-line.
Please address comments and questions to the library author, although keep in mind he is an abysmal correspondent and basically an asshole. Despite that, your feedback is very much appreciated. You may also open issues on github and/or sourceforge.
Thank you for your interest in c3p0. I do hope that you find it useful!
Note: c3p0 has had a good experience with reporting of a security vulnerability via Sonatype's Central Security Project. If you find a c3p0 security issue, do consider reporting it via https://hackerone.com/central-security-project