MP3s are so last century. As we’ve previously reported, Apple is moving iTunes to the cloud and is slowly signing on record labels to supply content. The latest company to fall is apparently Warner Music. The company signed a deal with Apple last week.

The iTunes cloud should work like a locker/streaming service. This would allow users to dump their music into the cloud and access it anywhere or, barring that, offer a monthly service to access albums on the go, a concept similar to Rdio and Spotify.

I suppose the biggest question is how Apple will handle huge collections of music that most active MP3 users have squirreled away over time. While purchased titles will be simple – they’re simply a symbolic link to a central “gold” version – there is no clear way for Apple to support the uploading of 500 versions of “Hey Soul Sister,” all of slightly differing lengths and titles.

AllThingsD has more information on the deal noting that it is just like Amazon’s locker service but with one important caveat – Apple is actually getting the label’s permission to offer the service.