I came across this web site the other day, it's got 9 downloadable episode transcripts (ASCII format):
http://home.cdsnet.net/~nikko11/seinfeld.htm
The episodes are: The Bris, The Stakeout, The Pez Dispenser, The Airport, The Movie, The Outing, The Old Man, The Junior Mint and The Smelly Car.
BTW, there's also a shopping site with Seinfeld merchandise (T-shirts & caps):
http://www.ishops.com/moviemadness/seinfeld.html
Just 2 let U know, in case you didn't know already.
Andrew