BOINC, which we linked to and talked about a couple of months ago, was just written up in New Scientist, generating a fresh round of links. (BOINC is an application developed by the SETI@Home crowd as a generic distributed computing platform. It's open source, and set to be released next month.)
For those of you new to the world of distributed computing, it's a method of treating many (hundreds, thousands, even millions) of networked personal computers as a single pseudo-supercomputer. In this way, massive problems involving huge amounts of data can be inexpensively analyzed. It was initially made famous by SETI@Home, which chews on radio telescope data looking for possible signs of extraterrestrial intelligence. SETI@Home functions as a screen saver, only processing its data when your machine is idle. (Because the site lists just how many units of data any individual person has processed (across any number of computers), some folks have written viruses/worms to forcibly install SETI@Home on unsecured machines over the net!)
But BOINC and SETI@Home are not the only distributed computing projects out there. Rather than list them all, I'll just point you to AspenLeaf.com's Internet-based Distributed Computing Projects website, which is the best listing I've found for what's going on, what's coming up, and what you can do to help. There's even a link to a distributed computing chess program, if your computer would rather have fun in its spare time than fold proteins or look for alien life...