You need to go to the following site (LINK REMOVED) to make your location visible to others (outside of friends). When you do this a text box appears and within the generated code is your User ID. Without doing this you will get either an error message in the 'gadget' or a location unknown message.
It would be good if the original gadget code was integrated into the module so that you could customise even further and remove links to google latitude (giving away the magic).
Thank you Mickey, I will add a small instruction on my site where one can find the badge id.
Maybe in the near future I will create a version with more possibilities.