http://open.bbc.co.uk/catalogue/infax
I think this is exciting enough to warrant a post of it's own rather than a del.icio.us link, especially as it is built with ruby on rails.
I like the honest caveats.
DOES NOT INCLUDE
* Anything to listen to or watch... Sorry, but the programmes themselves are not available.
* Info about every single BBC programme, ever. It's a vast catalogue, but it's not comprehensive.
* A guarantee of accuracy. We're very proud of it, but we know there are mistakes.