Google has finally released Picasa 2.5 Beta 3 and it has some nice new features. The most notable of the features would be the screensaver option which can be found under the Tools menu. This feature was in Beta 2 but there are some additional tweaks that you can do to it.
When you click the “Configure Screensaver” option from the Tools menu you will see the Display Properties window pop-up and it should look similar to the screenshot that I took. You can then click the “Settings” button and it will let you customize multiple options. You can choose which folders Picasa will grab photos from, have it display images from your Picasa Web Albums, and choose the visual effects for the screensaver. I think the new “Pan and Zoom” visual effect is the best.
There are also a few improvements that they have made, such as to the movie file support, but it looks like they are nearing another release. The number of changes keep getting smaller and smaller so I would imagine that the final version is right around the corner.