Here are an even dozen educational opportunities that will teach you everything you need to know about Adobe Photoshop CS5 and won't cost you a penny.
1. From Adobe you will find getting started and what's new info here.
2. Also from Adobe you will find (about) 25 "learning Photoshop CS5" videos here.
3. You'll find the Adobe Photoshop Learning Center from NAPP (aka The Photoshop Guys) here.
4. There is one boat load of tutorials at CS5.org.
5. If you are looking for Photoshop and Bridge tutorials check out PhotoshopEssentials.com.
6. You can watch 10 content aware fill video tutorials here.
And here are Podcasts that will enrich your Photoshop learning experience:
7. Photoshop Killer Tips
8. Photoshop User TV
9. Adobe Photoshop Quick Tips
10. Photoshop with Matt
11. Photoshop from the Ground Up
Consume the resources is small manageable bites or you may end up with a severe popsicle headache (brain freeze).
One of the features that many folks rave about in CS5 is the improved masking ability, below is a video demonstration. It is part one of a two part video, you can watch part two here.