The first(second on earlier) and default tool in the Photoshop CS5 tool bar. Keyboard shortcut for Move Tool is V. This tool is not just the most used tool, it is most easiest tool available in Photoshop also. Basically it is used for moving pixels, layers, text etc. as its name suggests. There are some advance uses of this tool too.
To move any Layer in Photoshop just click on the Layer and drag it to any where in the canvas to move.
Auto Select Layer or Group must be enabled to do this.
If you don’t want the Auto Select option then just Right Click on the layer and you will see a popup menu with list layers under it. Select the layer from there and move it anywhere.
To create a copy of a layer just hold down the Alt key in your keyboard and drag the layer you want to copy. This option works with both Auto select layer/group enabled or disabled.
The Move Tool with Selections.
The move tool work almost the same way with selections but there are more options available.
If you just made a selection and want to move the selected area/pixels (not the selection), activate the move tool (press V on your keyboard) and then drag it using the mouse or use the arrow keys on your keyboard.
Holding down the Alt key will make a copy of the selected area on the same layer. White this selection is active this pixels are on a layer called Quasi-Layer, and the selection is called Floating Selection.
You can also create a copy of a Layer by pressing the Ctrl + J key.