As reported yesterday, Apple’s North Carolina data center has completed testing and lies in wait as record companies eagerly hammer out last-minute licensing deals for streaming, cloud-based music distribution. Warner Music Group, the recording industry’s third-largest company, is the latest to agree to terms with the computing giant.

Though Amazon was first to introduce such a program with its aptly-titled Cloud Drive and Cloud Player, those services went live without any major label support and don’t currently offer iOS compatibility. Since Apple’s latest earnings report pegged the active iOS user base at nearly 200 million, a lot of people felt (and still feel) hung out to dry. Meanwhile, as Google’s own innovation and roll-out in this department seems to have stalled considerably (leading to rumors of a partnership with Spotify), Apple is all set to change the way we listen to music. Again.

According to CNET, Apple has already signed two of the world’s four largest record companies to streaming deals, with iTunes’ chief Eddy Cue in position to ink the remaining pair sometime this weekend. While there may be a small challenge in getting Sony Music Entertainment on board (due in large part to Sony’s own iTunes-challenging Qriocity service), all four providers should be ready to deliver content as early as next week.

Now that the data center riddle is partly solved, iTunes users can expect, at the very least, huge portions of their individual music libraries to be stored remotely and streamed to any iTunes client or iOS device on their account. This means, simply and beautifully, that all your music can stream to all your devices without taking up any storage space! Unlike the App Store, in iTunes there is no way to pay once and download the same content to your iPhone, iPad, or iPod without syncing to a computer in between, and music recovery is a nasty chore. If things go according to plan, this new delivery system will ensure that music and videos purchased once are yours forever, accessible anytime from any place with a live internet connection. That 8 GB iPod touch suddenly seems so much bigger…

The forecast, ladies and gentlemen, is calling for cloudy conditions.

And Apple’s going to make it rain.