ProDesktop is now obsolete, but it was 3D CAD software for Windows desktops from the same company (PTC) that created ProEngineer. Now that ProE can be run on normal (albeit high spec) PCs real engineers don't need ProD. But here in the UK ProD has been given away 'free'* to any school that wanted it. Most will carry on using it for another 5-10 years I would guess. Some schools are already starting to look at ProE, SolidWorks or Inventor, but they are all expensive.
In UK schools the Design & Technology departments are often the heaviest users of IT, but they are rarely IT experts, they just want something to do CAD/CAM work on. The lack of a decent 2D/3D CAD package is major reason they won't consider Linux. In the end I expect the govt. will do a deal with PTC to import ProE and run it on Vista at great expense.
I've tried several packages. Some are 'Alpha' and not much more than a pretty GUI, others are old UNIX things with a primitive GUI that must be 15 years old. The best, cross-platform simple 2D/3D package I've seen is VariCAD, but it's not free (in any sense).
I'm pretty sure there isn't a suitable package out there. Anyone fancy building one based on the OSS that is available?
* Free as in "the beer's free, but you have to pay for a training course to learn how to drink it." Sounds mad, but actually it was a method for schools to 'buy' software they wanted whilst the government could boast how much it had spent on training!