Microsoft CEO Steve Ballmer will spell out the future of the company's many product lines at its Worldwide Partner Conference in Los Angeles this week.

The 15,000 attendees at the Staples Center, will also be treated to a session wiht Virgin Media chief Richard Branson as well as other Microsoft executives, including Satya Nadella, the new head of servers and tools; Andrew Lees, head of mobile; and Kurt DelBene, head of Microsoft Office.

This lineup of speakers suggests possible updates on Windows Azure, Windows Server, Windows Phone 7, Office and Office 365.

While Windows President Steven Sinofsky recently detailed plans for Windows 8, Microsoft's attempt to compete against the iPad, he will not be making a keynote appearance at WPC. However, Windows and Windows Live Senior Director Erwin Visser will deliver a keynote, and the long list of speakers includes executives from just about every product group as well as partner-focused divisions such as OEM sales, developer groups, hosting, telcos, ISVs and channel strategy.

Naturally, the Partner Conference focuses heavily on how software, hardware and hosting vendors can work with Redmond to sell products and services based on Microsoft software.

Microsoft directly and indirectly contributes to more than $500 billion in annual revenue across the IT industry, including partner services and software built on top of Windows, according to an IDC study sponsored by Microsoft.

Microsoft has to tread carefully to avoid conflicts with partners, though. Both Windows Azure and Office 365 have raised concerns about Microsoft cutting into partners' revenue streams, but those concerns have been eased somewhat by new partnerships with telcos to sell services based on Office 365.

After the serious keynotes on Monday and Tuesday, the Staples Center will host Richard Branson. Attendees can submit questions in advance to Branson, who will speak in a Q&A-style interview with Microsoft channel chief Jon Roskill.