>Does anybody know how to get ICS (Internet Connection Sharing) to automatically disconnect from the phone line when a remote computer closes it's connection? I've looked at the MSKB #Q230108, but that doesn't seem to help. It seems to only apply if you're on the machine running ICS, not one of the remote connections.

You should be able to set the connection to drop after a fixed period of inactivity on the connection - Dial Up Networking, pick the connectoid, right click, pick Properties, General tab, Connect using Configure button, Connection tab, call preferences, check box and delay time are there.