When I opened Picasa up this morning, it wanted me to update. When checking the about page, lo and behold, Picasa 3 does not say 'beta' any longer!
Interestingly, the Google site shows Picasa 3 as still being in Beta. But, installing the downloadable exe shows that it is indeed the finalized version of Picasa 3.
If you are unsure, you can open up Picasa and check for updates (help> check for updates) - it will pull the latest version for you.
Trick or treat everyone - have a safe and Happy Halloween!
Here's a video overview of Picasa 3's new features (OK, so the video says 'Beta', but you get the idea!):