Have you seen "Star Wars: The Clone Wars"? That show is well liked by much of the teen and adult SW fanbase and it is a big enough success to have gone on for several seasons now. A big plus is that as an animated series it is much cheaper to do compared to a live action series.
It is keeping interest in the SW brand alive until the next SW movies are released.
I've heard of it but not seen it. The first three films are so wildly popular that I'm not sure TCW is actually doing anything in particular (I think it's just capitalising on the innate popularity).
There was 15 years between Return of the Jedi and The Phantom Menace. I seem to recall from my childhood a pretty dismal 'adventures of 3PO and R2' Saturday morning cartoon, but it's hard to say that it played any particular role in the anticipation that led up to TPM's release.