Like with The Matrix film where they gave backstory in the Animatrix, Lucas wanted the same and got in Genndy Tartakovsky of Samurai Jack fame as well as Dexter's Laboratory and apparently Powerpuff Girls too.
The first volume was 20 5-minute episodes of fun, volume2 is 5 12-minute episodes and steps up the pace, racing towards the film with interesting info and setting the scene.
Being StarWars, membership of StarWars.com is important to view past episodes but for a short while after airing the eopisodes are free to all on:
http://www.starwars.com/clonewars/microseries/chapter/21.htmlVolume2 is currently available to watch, streamed Quicktime format and god knows how long they'll last.
It starts at episode 21 with the evil General Greivous from the new film after crushing a Republic battle group and hunting the Jedi Commanders.
They called for help so the Elite Arc Troopers turn up, all business-like.
Check out the first one at least.
The episodes are quite varied and the last episode or two explains the start of the next film.
And it ain't no happy kiddies crap with long-eared prats.