How do I hide folders in OSX?
The command-line way:

Open Terminal (/Applications/Utilities) and type

chflags hidden /path/to/folder


replacing /path/to/folder with the POSIX-style path to the folder you want to hide (for example, a folder on your desktop called test would be ~/Desktop/test).

To unhide it, type chflags nohidden /path/to/folder.

The freeware way:

I haven't used it, but I've seen the app Hide Folders, by Altomac.