So the other day I was following an email thread on a discussion forum for Virtual Earth internally here at Microsoft and someone says, "if only VE clients had “inertia” like Google Earth..." and someone writes back. "Inertia is there, it's just turned off by default" WHA??? How'd that get in there? I wasn't alone in my surprise it seems as others as well didn't know that either. So I guess we snuck it in there. Anyway, if you want to turn it on here's how you do it.
Open up Virtual Earth and turn on 3D mode.
Then click on the Options button. This thing ->
Next click on 3D settings.
Then click on the Preferences tab and then click on the checkbox in the Mouse preferences section.
And THAT'S IT. Have fun flying around in 3D with Inertia.