if you mean the actual process of making themthen that's more a case of trial and error, with photoshop you can find quite a few tutorials online to help you get used to it.
hotwired.lycos.com/webmonkey/design/graphics/tutorials/tutorial1.html
(hotwired.lycos.com/webmonkey/design/graphics/tutorials/tutorial1.html
Professor Fnord Regius Professor of B3ta Chronology,
Tue 11 Jun 2002, 5:38,
archived)