Here's an [link=http://cgi.ebay.com/RC-Flight-Simulator-Mac-OS-X-Fun-Easy-to-Learn-to-Fly_W0QQitemZ190120269431QQihZ009QQcategoryZ34056Q QrdZ1QQcmdZViewItem]eBay auction[/link] that's selling a controller with the CRRC simulator that jerstamb mentioned along with instructions on how to install it in Mac OS X. It's about $33. According to [link=http://crrcsim.sourceforge.net/wiki/index.php]CRRCsimWiki[/link], however, it doesn't look like it supports helicopters, only fixed-wing crafts.