This plug-in, like many of the others, allows you to upload photos from your iPhoto library with a couple clicks. You can also add them to different sets or create a new set right from the export window, set the privacy levels, and resize the picture to your specifications. The only thing that you cannot do from the plug-in is add a description to the photo; however, once the picture(s) are uploaded, it takes you to a Flickr page to fill in this information. Overall, this is an excellent iPhoto to Flickr plug-in if you don't want a paid plug-in.
FFXporter is available as a free download from the developers website.