Telegraphics Adobe Photoshop and Elements plugins
"In general, each plugin can be used with all versions of Photoshop (3.0-7.0, CS, CS2), under Mac OS X, 9 and earlier, and Windows.

Should also work with other compatible programs such as Elements, AfterEffects, Premiere, PhotoDeluxe, Corel PhotoPaint, Paint Shop Pro, Fireworks, Painter, Photo Impact etc. (incomplete list)."

They also have information at the site for using these, and other Photoshop plugins, with the GIMP (on Linux).