I just came across and tried a new free browser plugin that generates a great full screen slideshow from Flikr, Google Images, Photobucket, and social networking sites. http://www.piclens.com
In Firefox on a Mac running Leopard it worked great. Safari was not successful for me, though. The interface is very simple and intuitive and the design is nice, sleek and iPhoney. For the price ($0), it seems hard to beat. These guys also have a free slideshow that can be embedded in a website to avoid the need for viewers downloading a plugin. I will give that a try soon, too. I have no affiliation with these people, but highly recommend checking it out.