My biggest beef with the Vudu set-top movie box is that it’s always been a one trick pony, and an expensive one at that. Focusing on paid-for movies (rentals and to-own), Vudu’s sole proposition was that you purchased one of its set-top boxes, starting at $299, so that you could begin purchasing content. Essentially paying to enter the store.

That changed today, with the company announcing support for a range of free online video from YouTube, MSNBC, CNN, MTV, PBS, and National Geographic, as well as images from photo sharing sites Flickr and Picasso. “The new content will be available via a free firmware update that should hit all Vudu boxes over the next 24 hours”, reports Cnet. And best of all there’s plenty more to come.

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That’s because Vudu isn’t providing access to said content through formal licensing agreements but is instead pulling in content through those sites’ own APIs or freely available web feeds. Better still, Vudu is going to open up this feature to third-party developers in the first half of 2009 who’ll be able to add support for more online content.

In other words, Vudu looks like it might be slowly morphing, to some extent at least, into the open Apple TV I’ve been long calling for.