My "missing images" tool, a toolserver script to find free images to use in WIkipedia articles by looking at what other langues have about the topic, has been running for almost a year now, and was used ~42000 times. Recently, I published "WatchFlickr", which does a very similar thing, but searches free Flickr images.
Enter the FIST (Free Image Search Tool), a "unified" version of both tools, and then some: http://tools.wikimedia.de/~magnus/fist.php
It has the known, now "merged" features: * Follow language links and look if they have free images * Look on Flickr for free images I have added: * Direct Wikimedia Commons search (results from the internal Commons search) * GIMP-SAVVY (lots of PD images from the US Gov.)
Together with a truckload of options (scan title lists, categories to depth X, replace placeholder images) and fine-tunings for the individual searches, it is already likely to be one of the most comprehensive free image (meta-)search tools on the web.
Please try it out, report bugs and feature requests (link in the header bar), and throw lots'o'images at wikipedia articles :-) Both Missing Images and WatchFlickr will eventually be "phased out" and redirect to FIST.
If you know any other sources of free media, I'll be happy to add them, provided * they have at least a few thousand images * they have an API, to are easy to screen-scrape;-)
Cheers, Magnus
P.S.: Sorry to spam wikipedia-l with this, but it seemed significant to me, and the easiest way to reach wikipedians in all languages.