The apple.com site posted a message yesterday saying, "Tomorrow is just another day. That you'll never forget [...] Click back here tomorrow for an exciting announcement from iTunes."

Below that are four clocks showing the time of the announcement in California, New York, London and Tokyo.

The rumour mill went into overdrive yesterday, attempting to either decipher or second-guess the message.

The top three rumours circulating on tech blogs are: a subscription-based version of iTunes; a cloud-based version of iTunes; ...