Jon and Leigh Hicks from Hicksdesign bring us a cool, quick slide show explanation of how to do design a icon.
And if you don't know them, they actually designed the Mozilla Firefox and Thunderbid logos. These dudes are really good.
There's nothing better than to play with the tool if you want to learn it. Bert Monroy always mentions that on his podcasts and I truly agree with him. I think the best way to learn is trying to recreate images and effects we like.
Here I list my 10 tips to improve your skills in Photoshop, but they can be applied to other tools as well.