Photoshop Tutorials - Layer Transform
Every layer can be transformed just as the selection or selected area of the image. You can turn it, change its size and distort it. You can move the layers with the Move Tool. If you keep Shift pressed then the layer will be moved either vertically or horizontally. If you keep Alt pressed then you will get the copy of the layer.
You can transform the layer in Free Transform mode. To do this you can either select Free Transform in Edit menu or press Ctrl+T. The operations you can perform are similar to working in Free Transform mode with the selected areas.
There is also a Transform set of commands in the Edit menu that allow you to make more precise transformations to the layer. First five commands will bring you to the Options panel where you can play with their settings and make needed transformations. There are also options that let you rotate by 180, 90 CW and 90 CCW as well as flip the layer vertically or horizontally.