Picnik, the solid suite of photo editing tools, has just announced the release of "Picnik-in-a-Box," its development API. Now any web site can integrate with Picnik free for charge. According to Picnik, the new Picnik-in-a-Box API should enable anyone with knowledge of HTML or server-side scripting to quickly integrate photo editing int0 their website with some custom design aspects.
Personally, I find myself leveraging Picnik more and more these days as its tools have been integrated into Flickr. Picnik has also integrated with Box.net and Webs (formerly Freewebs). If you are interested obtain a software key which gives them instant, free access to the Picnik API.