When installing SketchUp, Google Earth or even Picasa, Google is also installing something called Google Updater. I couldn't really figure out how it was being started. This thread discusses it. In short:
launchctl list | grep [Gg]oogle launchctl remove [0x0-0xe00e].com.google.Updater.helperThe hexadecimal value is part of the grep output (so this will probably be different)
