Tried to login (from www.icloud.com or the Windows control board) - tells me to use my MobileMe-account (unused for years) - doesn't work - and blocks me from creating an iCloud account.
Waited for a chat (took hours) - and the chat tells me that iCloud doesn't work with Windows.. i.e it doesent work with iTunes for Windows (10.5.2)!!
Just tried to login again - same (negative result) - seems to be a good moment to leave the Apple "stuff" behind
You might want to wait until later on. I managed to complete all of the functions to move my accounts to iCloud by 9AM Eastern Time. The problems seem to have started about 10AM...