The Build 14.0.4514.1009 from Microsoft Office 2010 Beta branch that was leaked in the wild 2 weeks back is now officially available for download, well at least for subscribers of MSDN and TechNet. The beta of MS Office 2010 is expected to launch this week,  but subscribers to Microsoft’s MSDN and TechNet Web sites can get it now.

The most significant change in this build is the new installation procedure for test versions of Office 2010 SKUs. Previously, setup used to ask for product keys after it has been initiated, but now, starting from Build 14.0.4514.1009, Office 2010 will ask you for a special unique installation product key before setup has even started, thus making it difficult (not impossible) for those who try to leech through illegal sources.

On Monday, Microsoft released the beta bits to MSDN and TechNet early, as it often does for the networks. It also released the 64-bit beta version of Office Web Apps – the lightweight, online version of Office – to MSDN and TechNet on Monday.

Microsoft is expected to officially release the Office 2010 beta this week at the Professional Developers Conference in Los Angeles, running Tuesday through Friday. A tech preview was released in July, but was still lacking some features and polish. The Redmond software giant is also making a bit of a departure by offering browser-based versions of Word, Excel, PowerPoint, and OneNote. Because a high-level executive is delivering a keynote speech Wednesday, industry followers suspect the announcements will come then.

Last week, an Office 2010 beta leaked to the Web, though a Microsoft spokesperson told ZDNet that version is NOT the same as the one released to MSDN and TechNet on Monday.

Here are some screenshots of the Office 2010 build leaked last week:

MS Word 2010 beta [Screenshot]

MS Outlook 2010 beta [Screenshot]

MS PowerPoint 2010 beta [Screenshot]

It’s unclear whether Microsoft will cap the number of Office 2010 downloads, a move that would duplicate the clumsy process last January when it launched Windows 7’s public beta, or whether it will simply limit time the beta is available, which is what it did with Windows 7 release candidate.

Microsoft has, however, promised to distribute millions of copies of the Office 2010 public beta. Are you planning to grab one?