Since you are preparing your files on a Mac, there is nothing to do but save the files and compress them in a .exe or zip for the PC and a .sit, .sea or .zip for the Mac. For those folks creating shaders on the PC, there needs to be a conversion done of the .cbr file that adds a resource fork to the file which enables it to be seen by the Mac platform. The object/geometry files do not need this conversion though.