Start/stop internet sharing from a script? Is there a way to start/stop internet sharing from the command line or maybe an apple script?

The thing is that I move around my laptop between home and work. At one place I get wireless internet (and thus I have to disable internet sharing), and at the other I get internet from an ethernet cable and set up the computer to share the internet to other devices by creating a small wireless network.

But it's getting a bit tedious having to go into System Preferences and start/stop the internet sharing every time I switch locations, so I would like to have a quick command or script to launch and do the switch on demand.

Any hints or ideas?
To start Internet Sharing from the CLI:

sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.InternetSharing.plist


To stop, change the load to unload.

Note that if you have the pref pane open when you run this you will not see the change take effect immediately (the UI won't update), but it does work.