1. Make a new image (ctrl+n), in this example i have used 477x250 pixels. Make the background black.
2. Press 'D' to reset the colors, then make the primary color red. Now your primary color is red and your secondary color is white.
3. Select Gradient Tool, change mode to Dirrecence (look at the image below) and use the type 'Forground to Transperant' (look at the image below).
4. Now just go crazy with the Gradient Tool on your image. Make new gradients until you have got the image exactly like you want it.
Now you should have something like this:
Press CTRL+U to get the 'Hue/Saturation' window up, change the hue and get the color you want (if you dont want the original red).Here is my final result:
