iCloud.com has been operative since last Monday. Thanks to the site, we have learnt about Apple's new storage service; which is already working, albeit only as a beta version. In regards the price, the first 5 GB are free, but if you want more storage space, you'll have to pay for it: 20 US dollars per year for 10 GB, 40 for 20 GB and up to 100 dollars for 50 GB. As Apple has already announced, your iTunes purchases aren't counted when it comes to calculating your storage space, so they'll be added to your cloud for free. There will also be specific applications for iCloud on its website, like an email account and calendar alongside other functions. For now, only developers can access the page. The rest of the mortals will have to wait until the end of the year, when iOS 5 will be available for all Apple devices.
Update. We now know the prices for the UK and the rest of Europe. According to the upgrade plan selected, you will have to pay:
10 GB: 16 € / £1420 GB: 32 € / £2850 GB: 80 € / £70