Apple has opened iCloud.com to developers for testing and drooling…
I got in this afternoon and checked the environment out. Things are looking mighty slick.
The initial components are Mail, Contacts, Calendar, Find My iPhone, and iWork. Within the iWork section you'll, obviously need to download Keynote, Pages, and Numbers for the iOS platform in order to take full advantage of the future functionality.
I am a member of the developer program, but haven't put iOS 5 on my iPhone yet (was waiting for a more stable version of the software). I think we're there now – will be updating tonight and will post some iCloud integrations later this week.
CBSNews has reported that pricing has been announced as well – looks like they are tiered, unlike iCloud's predecessor MobileMe, which was $99 annually. All users will receive 5GB of storage for free that will be added to any plan purchased.
The cheapest paid plan is 10GB (15GB total) of storage for $20 per year. The other plans are 20BG (25GB total) for $40 per year and 50GB (55GB total) for $100 per year.