If you're being serious, I'd reccomed checking out some tutorial websites for help with photoshop. Places like deviantart, tuts+, and YouTube might be good places to start. Also, just try googling 'photoshop tutorials' or 'photoshop basics'.
Besides watching video tutorials, you can also learn the basics with LevelUp for Photoshop. The game guides you step by step with examples to learn the most used tools in the program!
Along with the suggestions for some good tutorials, much of the answer will depend on how YOU learn best.
I am a combo of 1 & 2, with emphasis on 1. My wife is a combo of 2 & 3, with emphasis on 3. It just depends on the person.
One good resource for 1 & 2 is the Adobe Classroom in a Book PS CS __ , by Adobe Press. It has both the reading and then the doing, in a series of exercises. Those exercises are representative of real-world operations, and usually explore the multiple ways that PS allows the user to the same thing - the same end result is shown with several methods. As soon as CiaB comes out for my Adobe programs, I pick up a copy, and work through the exercises, while reading.
Considering the popularity of tutorials, I think that # 3 is a more common learning path nowadays.
Which ever path you choose, remember, you will never know everything about Photoshop. I've been using it commercially for almost two decades, and learn something new in these forums, almost every day.
Good luck and happy learning.
If you do like to learn with Video tutorials, there is of course tv.adobe.com, and I'd be careful about most youtube ones, besides excellent folks like: http://www.youtube.com/user/ajwood2001?feature=watch
or http://www.youtube.com/user/PhotoGavin for instance.
There are commercial sites, like Lynda.com, totaltraining.com and video2brain.com that also offer world-class training.
(disclaimer: I did a class in French with the last one I listed)