As noted on the main page, the PDK for WM 2 is now available. Go there now: http://www.world-machine.com/dev.html
Currently the PDK is only compatible with MSVC 2005, but the Express Edition of MSVC 2005 is still available allowing you to use this compiler free of charge.
Questions about plugins should go in the PDK Forum (http://forum.world-machine.com/index.php?board=4.0)!