Microsoft will webcast the opening hour of its Windows 8 and Surface RT launch Thursday,the company said today.

The keynote,which starts at 11:15 a.m.ET,is the only part of the day-long event in New York that will be publicly broadcast.Throughout the day,Microsoft will show off Windows 8,its own Surface RT tablet,and new hardware from some of its partners to the press and industry analysts.

Unlike Apple,which rarely webcasts its presentation--although it did yesterday,for only the third time ever,to tout the iPad Mini--Microsoft broadcasts its events more frequently.

For example,the Redmond,Wash.company webcast the opening of its September 2011 BUILD conference,when it introduced Windows 8.

Microsoft has already strutted Windows 8,the Surface RT and OEM(original equipment manufacturer)PCs,tablets and hybrids elsewhere.On Monday,for instance,it hosted an event in Shanghai.Steven Sinofsky,the top executive of the company's Windows division,participated.

While Microsoft has not released an agenda or disclosed who will take the stage tomorrow at the U.S.event,it's safe to assume that both Sinofsky and CEO Steve Ballmer will be tops among the latter.

Microsoft will probably also trot out a number of software developers responsible for creating"Modern"(aka"Metro")apps for the Windows Store,the sole distribution channel for Windows RT and an important component of Windows 8.

Windows 8,the Surface RT and OEM hardware officially go on sale Friday.The Surface,Microsoft's first-ever in-house tablet,has sold out its pre-order inventories in the U.S.and Canada,making the company's small chain of retail stores the only way to acquire one this week.

Users who want to watch Microsoft's keynote will find it on the company's website shortly before 11:15 a.m.ET,Thursday.