Conduit Suite is now available from dvGarage. It lets you "composite and analyze live video input on set, use nodal techniques in Photoshop (PC or Mac), use nodal compositing techniques in After Effects (Mac or PC), and of course, use nodal compositing in Final Cut Pro and Motion."
There doesn't appear to be a way to purchase the Windows filters for AE and Photoshop seperately fom the the $149 bundle special. Also, a bundle of dvMatte Pro Studio 3 and Conduit Suite is just $199 for now.
Update: Stu Maschwitz likes Conduit's phat nodes.
As noted earlier, much more info and explanatory movies on Conduit and nodal compositing can be found in the demo section of dvGarage Conduit pages, and on the blog Lacq’ing in Depth.