Then you have to check out the blog of Dimitri Gielis! A month ago he did a posting about how to integrate the Highslide JS thumbnail viewer (check out there homepage, they have a nice demonstration gallery) into an APEX application.
If you haven’t attended Oracle Open World 2006 in SF (like me), you have to check out his diary about OOW. You feel as if you have been there! 🙂