geocaching.com uses LOC files for its caches. If you are a premium member, then you have access to the GPX files. MacCaching was made around the GPX files. You can load a single cache or you import a pocket query. Initially, MacCaching didn’t support LOC files, so I created this wrapper around gpsbabel.
It is now a standalone LOC to GPX Converter for OS X (2.7mb).
Simply drop your LOC file onto the program’s window and a GPX will be generated.