Go to www.hotscripts.com and search on photo gallery. They have ones written in java, flash, php, perl ... you can choose whatever you want. Some cost m oney though but the majority is free.
I'm producing a Web site for a volunteer organization (translation: no budget), and they've asked for some form of photo gallery. I've seen applications where photos are brought up in a separate window, with a "next" and "back" button to scroll through the collection. Is this a PHP script? Any idea how to do this?