This does not make any sense...
All .pk3 files work on PC or Mac. Skins, Maps, Textures, Sounds...
Just download the .pk3 file you want and unzip the file.
You are going to need stuffit expander, but with that you can get any zip file you want.
I have been playing on a Mac since this game came out, and only a few .min problems have slowed me down.
Here are .min files to make the maps work...
http://www.p-edge.nl/macmohaa/download_minfiles.html
Here are some files...
http://www.alliedassault.us/
Here are some more files...
http://www.alliedassault.com