Thanks Creamhackered who told me, The English U.S version is officially launched for Windows 95/98/ME/NT/2000 The XP version will not be available till Thursday although I have been able to install this on XP and its working fine (with enabled alerts)
Apparent changes
Sidebar is on by default with all new messages.
Resizing of Message window is limited.
.NET Alerts functioning.
Well enough of that! where can you get it? we have a direct link ;)