Ok, in this tutorial you will learn how to create a basic line/wave. Make that line into a glow and add a gradient.
The first step your going to want to do is create a document in any size. I have a 450x150 pixels.
Select the gradient tool, and choose your two colors you want. One of which is going to be fading.
Make sure you have linear gradient selected before you begin.
Using the gradient tool make a line across the blank document and you should get a decent fade into the color you have chosen.
Next create a new layer by pressing Shift+Ctrl+n or by going to Layer>new>layer. Name it whatever you want, I named it to line 1.
Select the pencil tool, and draw a straight line across the document. To draw a straight line hold shift. Don't forget to press "D" to set PS's default colors. Also when you have set the colors to default press "X" to get white as a Foreground color.
Your image should now look like this (depending on color).
Go to Filter>Distort>Wave
Set the scale to 35 and 75 percent. Also fool around with this stuff.
Go to Edit>Transform>Warp
Once your done messing around on how it looks, apply the transformations.
Right click on the layer "Line 1" or whatever you chose to name it, and go to "Blending Options"
Choose outer glow, and set the spread to 9 and size to 8.
I know this not the best, you got to mess around with Wave Statics alot. I just applied on one on really quick. You can also add this to cool sig's or something.