This is the post where you ask or find Photoshop Tips about tricks and shortcut keys.
share some tips about photoshop and will get to know other photoshop users.

here are some shortcut keys for photoshop, it will helps you alot by not wasting more time by going to use mouse for work.

here it is,

1) - Press Tab will hide tool bar and palette, Shift+Tab will hide only palette.
2) - Press F button, it will switch between 3 different screen modes and give you more working area.
3) - Hold Ctrl will temporary make any tool into move tool until you release Ctrl.
4) - Ctrl+J will duplicate the current layer.
5) - Ctrl+Shift+E will merge all visible layers to one layer, Ctrl+Shift+Alt+E will make a copy of the original and merge all visible layers.
6) - Ctrl + D to deselect, Ctrl+Shift+D to reselect what you deselected.
7) - F12 = Revert to how the file was the last time you saved it.
8) - If you are working on a document in Photoshop and press Ctrl + Shift + S to save it you will see that photoshop will have it named as Untitled.psd But if you press Ctrl + Alt + S you will notice that Photoshop will have it named as Untitled copy.psd
9) - Ctrl+click a layer thumbnail to select the layer transparency.
10)-Ctrl+Alt+click between 2 layers in the palette to group them.

i hope it will useful for you. try it.
& also, if you know any shortcut keys of phootshop share with us.

i have found this links. there is more shortcut keys for photoshop.
check it out : http://www.smashingmagazine.com/2010/02/10/photoshop-keyboard-shortcuts-cheat-sheet-pdf/