During one of my jobs the team I worked with had to create a solution which allows to track a Mac whenever it gets online.
I just thought about making this little app a little prettier and probably offer it as a donation ware.
Yet, a short online research pointed me at Orbicule’s Undercover, a software, which not only allows you to track your Macs public and private IP addresses, but which also sends you screenshots and photos of your Mac’s environment.
Looks great to me.
If you don’t want to spend the money for Undercover, there’s an article on macosxhints including some perl scripts, that are supposed to do the same thing for free:
http://www.macosxhints.com/article.php?story=20060823112947376
I haven’t tested it, but it’s worth a try, I guess.