Hey - you can find the STL files on the Sourceforge repository, here:
[
reprap.svn.sourceforge.net]
The free version of Sketchup doesn't seem to import STL's, but I found I could import the STL files into Blender, then export them as a 3ds file, then import that 3ds file into Sketchup.
I haven't had any success exporting STL's from Sketchup with the Su2stl.rb script, but I think Cadspan has an online plugin to do that. Also, I noticed that the scale was off by 25.4 in Sketchup - looks like an inch to mm conversion error. If you don't find a way to get the units right, you can scale the parts down by 25.4 in Blender.
Good luck! Dimensioned drawings would be nice, but I haven't seen any yet. I just print the parts and see if they're the right size.
Wade