Here's a cool tool with possibly the most awkward name ever: Flickr & WEBIMAGER. Yes, that's its name. It's a Windows app whose sole purpose is to take screen captures and upload them directly to Flickr. Simply use the built-in tools to capture the whole screen or a particular area, then click on the Upload button to give it a title and send it off to Flickr. It has a few other features like resizing, saving to disk, and some effects, and it'll also manage multiple Flickr accounts.