SETI is good en all and i used to do it. but it's so far failed to produce any significant results.
Do somthing worthwhile FOLD! (aims to find drugs that are effective at aiding / curing diseases) They have had results and are working to better human kind rather than searching for sensor ghosts.
See my sig for details of my work :-)
K
Edit forgot to mention there info site,
http://www.stanford.edu/group/pandegroup/folding/