UPDATE: You can now Download Here
As I'm still waiting for word from Adobe that I can post my Zenfolio and SmugMug plugins (“frustrated” does not even being to explain my feelings on this matter), I've put the time to good use, developing a plugin for Flickr.
To give a hint, here's what the export dialog looks like at the moment....
The SmugMug and Zenfolio plugins also got the ability to choose how the Title (Zenfolio) or Caption (SmugMug) is derived, as shown in the “Title / Description” section of this screenshot.
The Lightroom Export-Plugin SDK includes a sample export-to-Flickr plugin, and although I have not really looked at it since I tested a version of it a couple of months ago, I've heard that it's fairly bare-bones from a Flickr user's perspective. Mine, which I hope to release soon, is perhaps a step toward a more complete user experience.
(I should explain that the consulting I did for Adobe was to help test and debug the SDK and its “Lightroom SDK Guide” documentation. In order to help ensure that the documentation was correct and complete, I explicitly refrained from looking at the sample code. Thus, I had to read the docs and try to understand things that way, and as a result, I hope I was able to provide better feedback for them. I didn't use it as a Flickr user, either, because I'm not a Flickr user.)
Since the SDK's Flickr plugin was for demonstration, it contains some things I would prefer not to see in a real plugin, such as the various items it adds to the File and Library menus. My plugins don't add any of those. (I may add a “show these images at XXXX” entry to the Library menu, but there are some issues still to be worked out, such as where on earth I can find the time.)
Since I'm not a Flickr user, I'm not entirely sure whether I've grouped things reasonably, or what missing features would be most appreciated. I'd like to have a “replace” checkbox, but one needs a Pro account to replace images, so if someone at Flickr wants to comp me a pro account, I'd be able to write that Oh, and Flickr, if you want to give me written permission to use your logo, I can add that branding to the dialog header, as I've done with the Zenfolio and SmugMug plugins.