I am unable to consistently get screen sharing in iChat to work. When I select an online buddy, under the Buddies menu the options "Share my screen with Bob" and "Ask to Share Bob's Screen" are disabled. Sometimes starting a chat with that person will enable the screen sharing but often not. Once its enabled it works fine but I have no idea what the key is to getting it enabled. It seems fairly random when it works. This is over the public internet using Google Talk. Both ends are running OSX 10.5.