5/12/2007
The original web site http://www.libspf.org seems to have disapeared, so following are two links to cached copies of the last published version libspf
libspf 1.0.0-p3 - locally cached libspf 1.0.0-p3.tar.gz
libspf 1.0.0-p3 - web.archive.org cached libspf 1.0.0-p3.tar.gz
Also, there seems to be a somewhat out of date mirror @ http://libspf.userfriendly.net

11/24/2007
The original domain has come back online, but it is an archive site, not the original author's

Current - spamilter-0.60.tgz - 11/27/2005

Old - spamilter-0.59.tgz - 4/10/2004

Bleeding edge - Here is a on the fly snapshot of my working source.

n.b. This snapshot contains work which is yet to be released (mostly).
It may not compile, or if it does compile, it might not work like you expect.
This is not a "snapshot" at a time in point where things seem to compile and work as desgined and then saved in a tar ball, rather this is literally my currently running version/work in progress source.
It may also contain local policy changes, some or all of wich may, or may not make it into the next release.
In fact, I do not consider this to be any form of a release at all, but a window into my current work.
Use its contents at your own risk, or if instructed to do so by myself.