When you have something selected in Photoshop CS4, you can make a copy of it without copying anything to the clipboard and pasting it in the photo again. All you have to do is select the move tool in the tools palette and then hold down the option key on a Mac or the alt key on a PC and drag the image to the side. This duplicates the selected portion of your image. You can repeat that process over and over again for multiple copies of the same selection.
That's what I did to the zebra photo you see here. I worked on a high contrast black and white image and then I added the color after I had this "herd" of zebras. I added the color by simply making a new window and using the gradient tool to create a blend of color. Then I pasted the black and white zebras over the color and played with the blend modes until I liked the result.
The "blend modes" can be found in the layers palette. There is a submenu there where you see the word 'normal'. These blend layers together in various ways, and some of the effects will be good and some won't work at all. It's just a matter of trial and error.
Top stock photographer Jim Zuckerman is the instructor for many fine online photography tutorials, including two on creating Photoshop art: Creative Techniques in Photoshop and Advanced Creative Techniques in Photoshop. In addition, the BetterPhoto digital online photography school offers a number of other outstanding online Photoshop classes.