Make a new document 800x600 (white)

Download some grunge brushes from deviantART

To install the brushes download WinRar and extra them to Program Files>Adobe>Photoshop>Presets> Brushes

Use the brushes to make a pattern on your back ground, then colourize it, this is what I came up with


Now take an image I just done a random search on google

Carefully cut it out and paste it on your layer.

Now go up to Layer>Add Layer Mask>Hide All, the image should disappear, now take your gradient tool with these settings



Go over your image with it a few times until your picture like mine



That is you basically, I added in a few extra details

Here is my finished result