Here’s an excellent tutorial on Photoshop techniques — includes sample code, plenty of screenshots, and detailed step-by-step instructions:
In Part 1 we will create a very original design for all the comicbook fans out there. We will create this blog layout from scratch using several tricks in Photoshop to make it look awesome. Then in Part 2 we will learn how to slice it, code it, and get it ready to be converted into a blog CMS theme.
— Alvaro Guzman @ Webdesigntuts+
Note that Part 2 is not yet published.