I'm not rooted. I went to the Market do update to the newest Google Maps version (I had the stock version and needed to "install" it again). However, I decided to quit the Android Market for some reason. Also, to note, it was the old version at this time.
Then, after 30-45 minutes, I opened the market again and it was the new one! It was a bit slow at first but I quit and opened it again, and it worked fine.
So...maybe for all you non-rooted users, just open the market once, close it, and see if it is updated after a few minutes or so (I didn't get any notifications or anything).