I am in the process of writing this up for someone else and decided to adapt it for a DA tutorial. This first part covers the basics of how PS brushes work and their settings. The second part is here: [link]
and will cover customization and brush blending modes and answer some questions. A lot of this I've already gone over in various forms and places, but now I'm gathering it all under one roof, so to speak.
See any mistakes, inaccuracies, typos, confusing parts? Just let me know - and thanks!
Note: None of these deal with the CS5 natural media brushes. I'll probably write up a separate document on those.
edit 10/28/10 - thanks very much for the DD on this tutorial, glad people have found it helpful! And thanks very much Aaraujo for suggesting it and shelldevil for featuring it!