I've been using Picnik.com for some time now to edit photos for our Grizzly Mountain Arts items, and I've also used Flickr as an online portfolio of our work. Recently, Picnik.com has created a wonderful new utility that makes slideshows from your Flickr sets! It's all integrated--you click on Flickr from within Picnik, then select the set you would like to make a slideshow presentation from, then Picnik generates the html for you.
The slideshow above is from our Flickr "Tatting Shuttle" set. If you would like to view more of our Grizzly Mountain Arts Flickr portfolio, please click here.