1. in a way - opened it, got mad at it and closed it. I learned most of my l33t photoshop skillz from Paint Shop Pro - cheaper alternative to the Photoshop but basically the same thing.
2. Not too hard to learn but it can be tricky. If you want to learn I suggest just opening up and playing with it. Figuring out what the controls do, maybe read some basic tutorials. I taught myself so it's not too bad.
This place has some pretty good tutorials: