OSX has a VNC tool built in called Screen Sharing, this lets you access other machines running a VNC server.

You can use the GUI but I’ve found the best way to is simply to launch it via terminal (while connecting to a VNC server), here are some examples:

open vnc://www.myserver.com
open vnc://192.168.111.145
open vnc://mylocalserver.com

Safari supports these urls as bookmarks for easy VNC url management or you can use something like quicksilver for quick key stroke launching of VNC sessions.