Publishr is a quite useful GIMP plugin. With Publishr, you can directly upload images to Flickr and Picasaweb from GIMP. The latest version of Publishr is 0.2. You can download it at here.
We have examined several applications for working with Flickr before, and they all have one thing in common: they focus on uploading images from the desktop. But uploading only scratches the surface of what the Web service can do. Desktop Flickr Organizer (DFO) gives you a lot more power.