…for me the following did the job:
- cd /System/Library/LaunchDaemons/
- sudo launchctl load -w com.apple.screensharing.plist
where sudo launchctl unload -w com.apple.screensharing.plist would disable it. Worked for me in Lion. Might work in older versions too.
via 10.6: Start screen sharing remotely in Terminal – Mac OS X Hints.
Works also in Mountain Lion