Google has a fun addition to their map software called Latitude. Basically, it figures out your location, and allows people you specify to see that location on a map.
They've put out a cute "toy" to advertise it. You can see it at http://services.google.com/latitudevideo/view.html#n0CvZxmd5m0Ehmc5z05s0CvZxmd
For once, this is an app that works on my phone (Windows Mobile) but NOT on Wendy's iPhone. At least, not yet. She's stuck with using it on her MacBook. ;)