You can always go into Activity Monitor and kill it (or do it via the Terminal console), but it doesn't permanently get rid of it. They install it silently in the background without asking and I have found this incredibly difficult to permanently delete, it keeps coming back! And worse, it sometimes can get stuck in a mode where it's churning the CPU on my Macbook causing the fan to come on and the battery to be eaten up quickly. For some strange reason, Google insists that any Mac user running their apps (Google Earth, Picassa, etc.) must also constantly run the Google Software Update daemon.
