I encountered exactly the same problem running Fedora 10 64-bit host with Windows XP guest. I was able to fix it by forcing the Google Earth plug-in to use OpenGL mode instead of DirectX. I followed the instructions for modifying the Windows registry from this thread:http://groups.google.com/group/google-earth-browser-plugin/browse_thread/thread/5d5c7b7c90450de2/ee45771ce4a4d6a2
I first tried only disabling DirectDraw and Direct3D acceleration using the dxdiag.exe tool (and rebooting), but that did not work. It was only after I modified the suggested registry key (and killed all geplugin.exe tasks) that the Google Earth plug-in appeared at the correct size.
From the Google Groups thread:
You can control whether DirectX or OpenGL is used by changing this
0 = DirectX
1 = OpenGL
After making the change, you'll need to kill all geplugin.exe
Start -> Run -> taskkill /f /im geplugin.exe
or else the registry changes won't stick.
WARNING: only use this for testing, as this may change in the future.
Hope this works for you.