Download these http://www.deviantart.com/deviation/16435348/ - credits goes to omj for making these

Easy background

Start off with a new file doesnt matter what size

Make a gradient with these colors b2b2b2 (for grey) and ffffff (for white)
Then make a gradient like in my pic



make a brightness layer and make brightness to –25

Above the just added brightness layer make a new layer

Brush a bit on it with the brushes i gave to you use a white color



duplicate the layer and use a gaussian blur at 2 pixels and lower the opacity a bit
Now merge the two layers



Go to filter > sharpen > sharpen and sharpen two times

Now use the eraser tool (use the same brushes to erase some parts)

Btw you can also invert the layer with the gradient on it by pressing ctrl + i this gives a nice outcome too

normal:

inverted: