Besides Skim, what OSX PDF viewers support SyncTeX?
If you don't mind using macports you can install okular:

port install okular 


Consider editing the port file if you want to use kile (KDE's TeX editor) as well, as it depends on texlive and most mac users already have a TeXlive installation through MacTeX:

port edit kde4-kile
#remove the line which contains texlive
port install kde4-kile


After installing okular (and optionally kile) open okular and go to Settings > Configure Okular > Editor and insert the command to start your favorite editor( %f stands for the path, %l for the line). This question on tex.so describes the setup for kile.

Finally click on any part of the PDF while holding shift to use reverse sync.