The Inquirer confirms that Athlon64 FX processors selling on retail will indeed come with an unlocked multiplier. They are also reporting that you can get a free game when you register your product with AMD, and while the title hasn't been announced yet but The Inq does well in hinting it could be a recompiled version of a game taking advantage of the 64-bit features.
These chips will be completely unlocked, but you will pay a premium. Nothing is free anymore.
In the meantime, while the FX doesn't seem to be widely available yet, our pricewatch section gives us a good idea how popular the 3200+ will become taking already the #1 popularity spot in the CPU section and available from many retailers.