Windows 32 & 64 Bit XP/2000/Vista/Windows 7.
32 & 64-bit Autodesk 3ds max. Supports Max 9, 2008, 2009, 2010, 2011 (Max bug causes slow loading with external plug-ins), Max 2012 soon.
Why would I use plugin3D?
Suffice to say in this FAQ, that you will create better designs, much more quickly, with less effort and be able to commercially exploit them far earlier.