Bothering about the Pixel Bender Toolkit? It is just a pain in the ass to work with an code editor that even does not provide simplest text selecting features as textEdit.
Joa Ebert developed a very nice Eclipse Plugin for Pixelbender coding, which also compiles Pixelbender code before compiling and launching your SWF. This saves a LOT of time. There is no need to open the Pixel Bender Toolkit at all.
Last thing I am waiting for is a command line compiler from Adobe to allow one and two channel inputs. That would be great for audio processing. I am pretty sure, Joa would implement the compiler in no time.