Congrats
but if you wanna crunch hard just get yourself a 1.6 or a 2.2 p4 Dell laptop on eBay for about $1700 less than your powerbook and crunch much faster. i did a l ittle experiment, a co-worker of mine just bought the new 17" 1ghz G4 Powerbook,, with all the trimmings. she paid $3200 for it and it doesnt do SETI units as fast as my old Dell P3 1ghz.
Just my 2 cents worth, if youre die-hard Apple go for it. all my G3/500 iMac on my desk at work does all day is SETI