This tutorial is easy and quick to do. You can use this for a number of designs you do. I'm just going to show you a quick way I make them. If you need help, just ask. =]
Make a new canvas sized 305x115 (your size really just depends what you want). Duplicate your background in your layers panel. Go to your Blending Options on the duplicated layer.
Apply a gradient overlay of any gradient you want. I have my style set to linear and my angle set to 15. This is an example of what your screen should look like. Press 'OK'. Merge your duplicated layer down and then re-duplicate that layer.
Go to Filter>Noise>Add Noise. A box will pop up and this is where you'll do the noise level (sparkle level) of your glitterfill. I have mine set to 44.70% on Gaussian and I have Monochromatic checked. It looks like this:
This is what your glitterfill should look like when you are done.