I spent about a month programming Photoshop plugins. I found it very difficult to get the output that you wanted and the whole thing was frustrating. It involves A LOT of math and geometry to get the desired effects. If you want more information on programming Photoshop plugins, there are a couple of good sites on my links page. Before you download any files, please read the disclaimer and my agreement on the main page.
SMB Filter Collection Version 2.0 (splug.zip) This collection has a total of 18 Photoshop filters. They aren't very fancy because I didn't spend much time learning how to program Photoshop plugins. Some filters include: Vertical Waves, H-Light, Light Rings, U-Waves, Colored Pinwheel, Convert To B/W, TV Snow, Bottomless Pit, Revolve Image, Hills, V-Fan, and Sharpen Image. The zip file includes both the source files (*.afs) and the compiled plugin files (*.8bf). REQUIRES: Photoshop 4.0 or higher.