dstiles - 11:19 pm on Dec 22, 2010 (gmt 0)
I found a couple of web sites with the following line that needs to be typed into Terminal:
gconftool -s --type bool /apps/update-notifier/auto-launch false
I entered this a couple of days ago and today up popped the notification icon in the task bar. Now installing it on the second machine.
Downside: you can no longer just click on the icon. You have to right-click and choose an option.