Grunge Photoshop Tutorial

Create some text and rasterize it. Using the rectangular marquee tool make a selection as shown.

Now you need some kind of displacement map in .psd format (displacement map is simply any image you can use, but it must be a .psd). I have created two grungy displacement maps, you can download them here, or you may use your own.

Go to Filter>Distort>Displace, use default values and then navigate to the Grungy Displacement Map 2. Keep your selection active.

Press Ctrl+J (Mac: Command+J) to jump the selection on a new layer. Make two duplicates of that grungy effect you got or play around with more displacement maps to get the good grungy effect.

Now for the background. Make a new layer below all your other layers and use the gradient tool to fill it with gradient as shown.

Finally go to Filter>Distort>Displace, leave all values as they are and navigate to Displacement Map 2.

Extra:

Play around with the two Displacement maps or use your own images to see the effects you can get, either select the region you want to distort or use it on the whole layer, have fun!