Hi,
The FreeBSD port of postfix has spf on board since a few weeks,
but patches collided when you wanted to use both TLS and SPF in
postfix. I created a new port + patch from both the TLS and SPF patch.
The port can be found at
http://www.pine.nl/downloads/spftls/postfix.tar.gz. You can extract
the file in /usr/ports/mail and then do a install.
Thanks to Lutz Jänicke
(http://www.aet.tu-cottbus.de/personen/jaenicke/pfixtls/) for the TLS
patch and Dean Strik (http://www.ipnet6.org/postfix/spf/) for the SPF patch.
Please let me know if you have any problems.
greets
Patrick