Various machines have been used over the years. Currently contributing work units are a dual Pentium-II 800Mhz (FreeBSD 4.7) and occasionally a Sun Ultra-10 SPARC workstation (Solaris 9).
SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.