The SETI@home software for the Mac now has a client available for Mac OS X, and a recent update fixes a problem associated with the new OS. You can download it from the SETI site.
The new version, 3.0.4, works around a problem with the OS X 10.0 release that sometimes causes connections to fail when it first establishes an Internet connection using auto-connect. It does this by retrying automatically if the connection fails, so connecting to the SETI@home server may take a minute or two when autodialing via modem or PPPoE.
Besides Mac OS X, you’ll also need a monitor with the ability to display 8-bit color in 640×480 resolution (though 800×600 or higher is recommended in order to fit all the graphics on the screen). The instructions for installing and running this software on Mac OS X systems are packaged with the software.
The SETI@Home client downloads a portion of the data collected by the SETI (Search for Extraterrestrial Intelligence) project’s radio telescopes — most notably the gigantic Arecibo telescope. The client screensaver then analyzes a tiny portion of the data and searches for evidence of a signal.
By distributing the search workload to thousands of computers, SETI@Home has allowed the project to, in effect, log thousands (or more) of years of supercomputer time. Macs have contributed a considerable portion of this work time because the RISC core of the PowerPC processor is extremely efficient for this type of work.