Great, neat and simple Photoshop tutorial.

Those wanting to learn Photoshop in an interactive manner can read the tutorial hosted on the following website www.karbosguide.com/books/ap70.
The author of this website has posted an english translation (not perfect english though) of a booklet about Photoshop.
The booklet was targeted at Photoshop 7 but it is still valid for Photoshop CS3.
It contains a set of chapters and practical exercises dealing with all facets of Photoshop wether it's the toolset, layers, filters etc.
I highly recommend you completely read this booklet and do all the exercises in order to grasp the concepts behind Photoshop, concepts necessary in order to master more advanced uses of Photoshop like digital art and digital photography retouching.