I have released next version of publishr plugin, that allows one to save their images to web services like Flickr and Picasa right from Inkscape.
Download it from here.
More info on wiki. Changelog for 0.5 here.
This version should work on Windows Inkscape as well (unlike previous versions), however I don't know the extensions directory on Windows so couldn't test it myself, but I heard others successfully using it on Windows. Please give it a shot.
Any comments and suggestions are welcome!