Tutorial for the mega-n00b.
This is how to make a simple userbar\sig using Fireworks (could work with photoshop too!)
1. Get a good background. A photo, logo, whatever! I chose this.
2. Make a rectangle. Change it from a solid colour to a gradient. Pick your colours to match the scheme you have.
3. Set the gradient layer to overlay, and you're done. Add a render, your name, whatever.
You should get something like this:
As above, but 350x20 is the size you're aiming for.