thanks Phyllis!
It's a bit complicated, but yep, here's how to do it:
first you need to create the pattern:
1. File>New 15x15 pixels, Contents: Transparent.
2. Make Black your foreground color and Select All (ctrl+A)
3. Edit> Stroke, 2 pixels, Color: Black (drag selector to bottom left corner) , Location: Inside, Mode: Normal, Opacity: 100%
4. Image> Image Size, resize to 3 pixels
5. Deselect all
6. Edit> Define Pattern, Name: Grid (or whatever you want to call it)
Now that you have your pattern, creat a new image (whatever size you want maybe 250x250 pixels for this example)
and make a selection with the Eliptical Marquee Tool. Now choose the Paint Bucket tool, choose Fill: Pattern, Pattern: (choose the one you created, it should show up in your patterns drop down list). Now click inside your selection, and it should fill with the Grid pattern. now go to Filter> Distort> Pinch and choose whatever percentage you want in the "Amount" area for the look you're going for then apply the filter.
- David