mersenne.orgis the first site I am aware of that provided links to Internet-based distributed computing projects.
Parasitic Computingis a site about parasitic computing, a way to make networked computers unknowingly do distributed computation just through the act of communicating.
a primer on distributed computinggives a good overview of distributed computing for people who are interested in starting a distributed computing project
psio.netcontains a list of distributed computing projects and in-depth reviews of those projects.
Rechenkraft is a distributed computing links site written in German by Michael Keppler.
Team MacNN's site is a good resource for Macintosh users.
Distributed Computing Project/Platform Discussion Groups
Jason Nugent moderates a
discussion
group about distributed computing projects at
Yahoo! Groups. You can follow the discussion
interactively at the website, or have the discussion messages emailed to you
individually or in daily digests.
Scott Jensen moderates a Yahoo! discussion forum, DistributedBioResearch, for his non-profit charity which will support the Pande Group at Stanford University and their Folding@Home project.
Usenet group comp.distributed was created on February 4, 2002, for
general discussion about distributed computing and projects. If you don't
have access to Usenet directly, you can search Usenet archives at
Google Groups.
The SETI@home project is also discussed in the alt.sci.seti and
sci.astro.seti newsgroups of Usenet. These newsgroups are archived in
Google Groups.