There are two big themes at Microsoft’s Professional Developer’s Conference, just getting under way here in Los Angeles.

One is cloud computing. At this morning’s keynote, Ray Ozzie and others will present Microsoft’s cloud computing strategy. If it’s right that IT is moving inexorably into the cloud, this could be make-or-break for the company. Truth is, despite huge number of users for things like Hotmail and Live Messenger, Microsoft is not perceived as a web or on-demand computing company. That space belongs to others, like Google or Salesforce.com. Further, Microsoft has a problem that those companies do not have: how to keep its partners happy while embracing a computing model that may severely reduce their role.

The other is Windows itself. Vista’s image is tarnished: the wow started badly, and although the OS itself now works better than it did at the launch, its negative perception is beyond rescue. Windows 7 is Microsoft’s next opportunity to generate some consumer and user enthusiasm for Windows, and to stem the flow towards Apple. Tomorrow is Windows 7 day.

We’re also going to get insight into the future of key technologies like .NET, the next version of C# and Visual Studio, the Oslo modeling platform, Microsoft’s plans for identity management, and plenty more.

I’ll be blogging and tweeting as I can during PDC. I’m also keen to know what you think, whether or not you happen to be here in LA (the keynotes are being streamed over the Internet).