iCloud will ship to consumers this Fall. It lets you store content in the cloud and access it on various devices. It works with iPhone, iPad, iPod Touch, Mac, and even PC, and is free with the upcoming iOS 5 - also due out this Fall.
The iCloud web interface at iCloud.com has now been opened up to developers, and shows apps that can utilize it. You need to have an Apple ID and developer account to enter.
With the announcement of iCloud in June, Apple also announced the end of MobileMe as a service, indicating that Contacts, Calendar and Mail services had been reworked to work with iCloud. It makes sense then, that web apps for these things, as well as Apple's iWork, are featured on the beta site.
With iCloud, users will also be able to access any app, book, photo, document, etc. from any of their devices. More facts about iCloud can be found here.
When Apple first unveiled iCloud, it talked about pricing, and how competitive it would be in terms of music storage. Here's a chart they shared.
Now, they've provided a bit more info. "5GB of free storage is plenty for most people," the company says. "But if you need extra space, you can always buy additional storage."
$20 a year will get you an extra 10GB. $40 will get you 20GB, and $100 will get you 50GB.