According to WinRumors a first wave of Windows Phone 7 updates will reach Telus in Canada and Orange in UK tomorrow.
Telus has revealed on their website on the 22nd March that the update will become available no earlier than this date.
Tom Warren also speculates that a further wave will hit on the 5th of April for O2 and Vodafone UK.
AT&T has still not indicated when they will be releasing the update yet.
Read more at WinRomors here.
Thanks Just Visiting for the tip.