Fraser Speirs has updated his fantastic FlickrExport plugin for iPhoto to 2.0.1, ushering in a few key bug fixes an an API compatibility update. The specific bugs that Mr. Speirs squashed (murderer!) are the 'Waiting for Flickr' hangup the plugin could sometimes experience upon finishing an upload (I've been personally bitten by this one on occasion), as well as a nasty iPhoto crash upon upload.
You can grab the update from Fraser's update post on his Connected Flow blog, or from the main Connected Flow product page.
Thanks Nik Fletcher!