Last week, we posted a new revision of the Pixel Bender Toolkit (1.5.1) into the downloads area on Adobe labs. This version fixes a couple bugs from the previous release in exporting Pixel Bender Bytecode for Flash. Booleans should now work correctly.
A request we’ve had a few times on the Pixel Bender forum and over on twitter has been that we post the language reference and developer’s guide separate from the Toolkit download itself. Those documents are now available as well on the downloads page.