According to Apple’s new MobileMe transition FAQ page, users will be able to access their iCloud services from the web. Specifically, the site says:
Will I be able to access iCloud services on the web?
Yes. Web access to iCloud Mail, Contacts, Calendar, and Find My iPhone will be available at icloud.com this fall.
The FAQ also details some other issues that MobileMe users may be concerned about as their accounts are moved to iCloud. Apple says that photos, apps, music, and books do not count against the 5GB of free storage that comes with iCloud, and users will be able to buy more at a later time. It’s unclear how much additional space will cost, but Apple says it will explain more in the fall. As you’re likely aware, iCloud was announced during WWDC as a replacement for MobileMe. It will automatically store content across all of your devices and keep your mail, contacts, and calendar in sync across all devices. Users will simply need to sign into a new device to pull in all of their settings, photos, and more.