I did this for free using a screen capture tool called Copernicus that allows you to capture a quicktime video directly from selected portions of your screen. It was tricky because the frame capture rate was only 2 frames per second with the CPU load of google earth doing its thing. I got around this by changing Google Earth's flying speed in its preferences->touring tab. I was able to crop out the text at the bottom of the frame by sizing the google earth window to larger than 640x480 and then capturing only the center portion of the window. If you want to get 720x480, you need to make sure your window width is greater than 720 wide, which oversamples the vertical. This gets sampled down when you take it to video editing.
If you want to spend money on it, I seem to remember somewhere in the on-line Google Earth Plus or Pro documentation seeing something about being able to record Google Earth output directly to a video file. This would obviously be a lot better quality, without all the frame-rate handsprings I had to go through. I guess the money must have been more than I was interested in spending at the time.
PS. For an extra cool effect, start with the entire globe visible, and flick it west to east to get the world spinning, then click your location to get the fly-in to start. Its tricky to get it spinning at a slow enough speed, but the result is quite nifty.
