Lightbox2 is open source and was authored by Lokesh Dhakar. If you use this code, please visit his site and make a donation.
To use lightbox2 in your page, you will need to copy the styles and scripts in the <head> tag and the contents of the div class entitled "lightbox_image_links". You can add as many image links as you like to this div.
You will also need these navigation images (zip)
View the page source to see what's going on.