Check out the "Bike How To" thread "Curved Seat Post". There are several ideas how to bend a seat post.
I personally have done it with good luck by using 5/8 solid steel rod and bending it cold, its cheap (a 3 foot piece of rod at Lowes was less than $15, you can make 3 seatpost from that) , quick ( figure your length and angle), and easy ( bent the rod with a long pipe,I use a piece about 5 foot long and something REALLY strong to hold the rod, I use a hole in my sidewalk, bend to desired angle and radius) shim as needed .
Check out the "Curved Seat Post" thread. Dangerous Dan