Sony has reportedly signed on with Apple for Apple's rumored iRadio service. Many believe that iRadio will launch at this year's WWDC, so it's important for Apple to have deals with all three major music labels in hand ahead of the announcement.
It's still possible that Apple has other issues barring it from a full launch, but they could still announce the upcoming product on Monday. It's quite likely that it would be announced during the keynote that takes place on Monday. We'll have coverage if iRadio does end up launching.
iRadio is believed to function much like Pandora, with the added abilities of instantly buying and downloading a song from iTunes should you discover you like it. Expect it to feature targeted ads to support a free version, with a possible premium version doing away with those ads.