Just a quick post to let everyone know that with the release of v1.0.5, SPF has officially gone open-source. The code (and most recent binary distribution) are now available from CodePlex and have been released under the GPL license.
The decision to open-source SPF was an easy one. The biggest factor preventing several companies from implementing SPF in their production environment was the fact that it was neither commercially supported nor open source. By moving SPF to an open source licensing model, more companies will have the option to experiment and hopefully use SPF to protect their web applications.