Aliens do exist, its just a matter of time until we have proof. Who knows maybe SETI will prove to be a waste of time someday but until then its the best shot we've got.
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.