I marked this for CS2 because that's what I used, but it should work with any version of Photoshop.
This is a pretty simple thing to do; you don't need anything but default brushes and tools. But you can use it to make some complex, nifty patterns for yourself, for sigs and other things.
All you need is a
very basic understanding of the pen tool, i.e. how to make a curved line. Just one. With one curved line, and some notion of symmetry, you can use my tutorial to go from this to this.
Kind of like a
Spirograph.
So yeah, if you understand what the pen tool is, what layers are, and how to navigate menus in Photoshop, you can make these.
Look interesting?
Here you go. Have fun.