With Apple's Word Wide Developer's Conference looming, rumors are flying about the new cloud based music service the fruit company is preparing to launch. We already know the service will be called "iCloud," but what does it do, and why do we need it?

iCloud will be a cloud based storage system for all of your music. Don't have enough space on your iPod or iPhone to have all of your favorite tunes? No problem. With iCloud you can have all the songs uploaded in one central location and simply stream them on your device. Early reports say that Apple has signed agreements with the four big music labels so almost everything you see in the iTunes Music Store will be available in iCloud. There's some question whether this extends to music you haven't purchased in the iTunes Store, but Monday's WWDC will provide answers.

The crew responsible for hanging the banners for the event held every year in San Francisco have tipped Apple's hat regarding the iCloud logo. Shockingly... it's a cloud. Apple Insider was able to snap a pic and it's already been circulating the web.

WWDC will also reveal major changes for the next version of the Mac OS, code named "Lion," and a major revamp to Apple's mobile operating system, iOS. These changes coming to iPhone, iPad, and iPod touch are rumored to include a major overhaul to the notification system and the addition of widgets. We'll have to wait until Monday to see what that means.