Blue Flame

1. Open a new document (any size) and fill it with a clear black background.

2. Create a new layer and create a narrow white rectangle like so:

3. Now using the 'Smudge Tool' and changing the setting values of (strength:50%; Master Diameter:10px) - smudge the layer into something like:

4. Now Duplicate that layer and hold, press 'ctrl and u' - this will bring the hue/saturation window up, were you can change the color of the 'fire' do these values:

5. Lastly set the layer mode to: 'color' and your result should be something along the lines of: