These are four address you can write to to contact Seth. He's left Buffy now so that one might not work. But give them a try!
Seth Green
Seth Green
PO BOX 3175
Big Bear, CA 92314
USA
Seth Green
c/o Don Buckwald and
Assoc.
9229 Sunset Boukvard
Los Angeles, CA
90069
USA
I (Vezzi) wrote to the c/o Buffy address and I got a signed postcard back! Woohoo! It's not a real signature but it's cool anyway.