Almost non-existent. The problem isn't licensing (any more than the current licensing issues they're having). The problem is access to all the CDs.

You read that right: I know for a fact that Pandora gets its music by ripping CDs. No, really. I've been there and seen it happen. Crazy. You'd assume the record companies would send over the digitized files -- no such luck. They have one person dedicated to ripping CDs, full-time.

Anyway, last I knew, Pandora was trying to work out a deal with some guy who owned thousands of classical CDs. So as long as the company can manage to stay in business, Classical is probably coming.