It will take more than DVD's to learn photography.
And there is no such thing as MASTERING photography, Photography is Art, Art cannot be perfected however It can have a single person who is favoured above the others (which is all individual opinion!)
However there is ways to help you USE your camera better, not become a Better photographer.
You either have the skill of photography, or you dont!
It is all about Creativity, Composition and the rest is down to the camera (well technically you but the in-camera settings for capturing the light.)
Photography is a life long learning curve, You should NEVER settle in photography, Your style should always change if your hoping to be the best.
Along with photography, There is also photoshop you must learn to get the most out of your Photograph.
I myself am a Graphic Artist who likes photography, I take photography for the aim of editing the image later to enhance
I have been involved in Photoshop for 3 years, but only really the last year I have been using it almost seriously, I am still learning in the area of Photoshop For photography (I like to class photoshop for different things as it is Such a huge range!!
There is Architects, 3d Modellers, Photorealistic artists, Web designers, Banner design/ Sign design, Photography, Video, Animation Etc... there is too many fields that can use photoshop that make it almost impossible to learn how to use it for EVERYTHING, once you learn the tools and their use, You can do most of what you want anyway.
Too long, didn't read?
Photoshop goes hand-in-hand with Photography, Learn them both
Books:
How to Cheat in Photoshop (CS3) - works for all versions of photoshop tbh.
Photoshop Bible
Revision3 > PixelPerfect, Watch these, they get a new episode every... Tuesday I think.
Understanding exposure- Brian Peterson
The Digital Photography book 1 - 3 - Scott kelby
These should be good guides to start you off
I am also HOPING to create a series of photoshop tutorials from beginner to semi-Advanced level (for photographers.)
I am starting as soon as I get a good Mic for my Laptop.