There is another way to do it. This is what I pm'd to the others. This method will also keep it from distorting and gives you the ability to stretch/skew the text the way you want it.
open the picture you want to use for the fill. Click on your text tool & put whatever you want on top of the picture. Make sure your foreground/stroke is the only thing w/color/pattern. You want to use vector, not floating. This will create another layer. Once you have put your wording on it, click your magic wand. Click inside each of the letters until all of them are selected. Click on your picture layer & if it still says background, right click on it & convert it to raster layer. Once this is done, go to selections, invert. Then hit your delete key. There you have it.