Apple is reportedly poised to finish signing licensing deals with all of the Big Four music labels in the near future, setting the stage for the introduction of a cloud music service at WWDC in June.

Music industry sources confirmed to CNET that Apple had recently signed a deal with EMI Music, and Apple signed one with Warner Music last month. That leaves just Universal Music Group and Sony Music, both of which are said to be wrapping up their talks for a possible contract signing next week. If that happens, it will put Apple about two weeks ahead of the beginning of WWDC, set to kick off on June 6.

Apple's cloud-based music service is rumored to fit into the digital locker model, allowing users to upload their purchased music and stream it to another computer or iOS device. Unlimited music re-downloads may also come with the service, which is expected to be part of a larger revamp of MobileMe. Both Apple's cloud music service and the MobileMe makeover are expected to be introduced this summer, though as usual, Apple has not publicly commented on its plans.

When Apple does finally announce its service, it will be among the last of its peers to get in on the cloud music action. Amazon introduced Cloud Player and Cloud Drive in late March, while Google announced its own Music Beta earlier this month. The key difference is that neither Amazon nor Google secured additional licenses from the music labels before launching their services—a real sticking point for the music industry. Amazon argues that it doesn't need the licenses because customers have already secured licenses by purchasing the music in the first place, an argument that (at least) makes the music labels uncomfortable.

Apple has apparently decided not to play that game, though. If the rumors are correct, the company is dotting its I's and crossing its T's in order to ensure that its own offering is ready for the main stage. The music industry has already begun chattering about how Apple's service will have more options for this reason, but if Apple's planning to reveal it on June 6, we'll find out the truth soon enough. Now if only Apple would actually announce the WWDC keynote...