This is a dynamic dns client that can update your IP to your free dyndns nameserver.
So whats so cool about that in my car you ask?
You can set DynDNS Updater to check your IP address at any interval you want. So as you are driving (or the guy that just stole your car) there is a good chance that you will pick up wireless signal here and there. All it takes is a second for it to update your IP, upload an ftp log file with detailed IP info
(You can easily write a script to upload the logfiles to a server for your viewing pleasure), or notify you via email is already included with the app!
You can also take advantage of their email alerts. It can automatically send an email to your email account or cell phone email for an IP change or IP discovery.
This can be a very useful tool, and who knows could help if your car gets stolen as well. Its a free solution for those with wireless in their cars.
I think its a wondeful tool for carpc owners, and its out of your way in the system tray.