Step 1
Create a document with dimensions 10px wide and 1 px high. Color half of that document black and goto Edit>>Define Pattern. Press OK. Close the document.
Step 2
Create another document and make a new layer. Press Ctrl+A to select all and goto Edit>>Fill. Under the 'Use' option, pick 'Pattern' and select the pattern you just made. Press Ok. Your document should now be filled with lines.
Step 3
Goto Filters>>Distort>>Polar Coordinates press OK.
Step 4
You should now have a radial background. You can do many neat things with this technique.
Final Result:
