Here is an ongoing list of keyboard shortcuts that you are responsible to learn

Mac OSX
  1. Apple+N - New Window in any application
  2. Apple+W - Close active window in any application
  3. Apple+Q - Quit an application
  4. Apple+Shift+Q - Log out
  5. Apple+P - Print
  6. Apple+C - Copy
  7. Apple+V - Paste
  8. Apple+X - Cut
  9. Apple+A - select all

Photoshop Application
  1. Apple+J - Copy layer or selection to a new layer
  2. Apple - access the move tool while in any other tool
  3. Space Bar - access the hand tool while in any other tool
  4. Space Bar (while making a selection with the Marque tool) - reposition the selection while making it
  5. Apple T - Free transform selected pixels
  6. Apple/Shift/S - File Save As
  7. Shift (while in selection tool) Add too a selection
  8. Alt (while in selection tool) Subtract from a selection
  9. Shift - Constrain a move to a straight line or keep a transformation in proportion
  10. Arrow keys - used with move tool to move selected pixels on row at a time
  11. Apple S - Save
  12. Apple Z - Undo last step *add alt to undo multiple steps
  13. Apple D - Deselect
  14. Q - Quick mask
  15. X toggels foreground and background colors
  16. Bracket Keys make your brush size smaller and larger
  17. D reset default of forground and background colors to white and black
  18. Alt with delete fill with foreground color
  19. Apple with delete fill with background color
  20. Apple with space bar toggle to zoom
  21. Apple with + zoom in
  22. Apple with minus zoom out
  23. Apple/Shift I - invert selection