Google launched version 5.2 of Google Earth on the 14th June. Version 5.0 added the ability to talk directly to your GPS and 5.2 extends this to add the ability to view elevation, speed, and other data as a graph directly in Google Earth. In short what most other GPS mapping software lets you do already. I can see a lot of outdoor folk liking this though. Trip playback has been improved. There is also iPad support and an integrated web browser (Chrome everywhere?)
http://google-latlong.blogspot.com/2010/06/announcing-google-earth-52.html