Adobe Photoshop is not o much of a big deal to learn. It is an easy Software to use. Once you have learned  the basics, it will be a lot easier for you.
          There are many versions of Adobe Photoshop. But from my point of view, Photoshop 7.0 is the best choice for the beginners. I have learned many things in adobe photoshop but still i use Photoshop 7.0 because its so easy and simple to use.I have used the same Version in my Tutorials in this blog. 
          In the way of learning Basics, Short Keys comes first. There are so many Short Keys in Photoshop that it will be confusing if I tell you all at once. So, I am not going to tell all of them right now but some of the basic & important Short Keys are written as under:

BASIC SHORT KEYS:
Short Keys of adobe Photoshop:
Ctrl+N = New Page
Ctrl+O = Open Page
Ctrl+S = Save Page
Ctrl+C = Copy
Ctrl+X = Cut
Ctrl+V = Paste
Ctrl+A = Select All
Ctrl+D = Deselect All
Ctrl+B = Colour Balance
Ctrl+M = Curves (brightness)
Ctrl+E = Merge Layer
Ctrl+T = Transform
Ctrl+R = Ruler
Ctrl+I = Invert
Ctrl+Z = Undo
Ctrl+Shift+Z = Undo Forward
Alt+Shift+Z  = Undo BackWard
Ctrl+Shift+D = Reselect
Ctrl+Shift+I = Inverse
Ctrl+Shift+O = Browse
Ctrl+Shift+P = Page Setup
Ctrl++ = Zoom in
Ctrl+- = Zoom out

          As for the remaining Short Keys, I will let you know further in my Tutorials gradually.

IMPORTANT NOTE:
                Learn all the Short Keys above and move to the Next lesson where the Real thing starts.

GOOD LUCK.