The best source of information is the sourceforce website. It contains links to documentation, Peep demos, and other generally useful stuff. Otherwise, the Peep mailing lists can also be helpful. There are currently two existing mailing lists: peep-general and peep-develop. The first is used to address general issues with Peep, and is at the time of writing very low-traffic. The developer list is used for discussing new ideas, coordinating between developers, as well as helping people debug installations.
To subscribe to either mailing lists, please visit: http://sourceforge.net/mail/?group_id=15807. The Peep website can be accessed at: http://peep.sourceforge.net . It contains a demo of Peep's capabilities (the demo used at the LISA 2000 conference) and the original best paper presented at that conference in the introduction page.
If you're interested in creating sounds for Peep or are interested in the software used to do much of the sound processing for Peep, please visit the Goldwave webpage at http://www.goldwave.com.
Also, if you're an ALSA user and have any questions concerning your ALSA drivers, please visit their website at http://www.alsa-project.org .