How can I mount a remote SSH folder on Mac?
Transmit - The ultimate Mac OS X FTP + SFTP + S3 app can do this.
Another choice would be ExpanDrive - SFTP/FTP/S3 Drive but I think Transmit is the better option (I own both and am affiliated with neither).
There are demos of both programs available, so you can try both.
Note that Transmit is sold both through the Mac App Store and directly the developer (Panic). You would be better off buying it from Panic directly because of the impending sandboxing rules for the Mac App Store.