Desktop deployment is a fairly broad topic, covering various products, tools, processes, etc. We try to cover as much as we can in the Business Desktop Deployment solution accelerator (http://www.microsoft.com/bdd), on the TechNet Desktop Deployment TechCenter (http://www.microsoft.com/desktopdeployment), at conferences like TechEd, Microsoft Management Summit, and IT Forum. But most of that is one way: Microsoft providing information to the IT Pros.
We also try to stay involved in deployment communities, probably not as much as we'd like, but we try our best. The places that you are likely to see me online:
The MSSMS list probably gets most of my attention, for one important reason: it's delivered right into my Outlook inbox and I can reply with no special effort required. Visiting the others requires extra effort. (Yes, the others are available via RSS subscriptions, but they have some significant limitations, e.g. not providing the whole thread, that keeps those feeds from being terribly convenient or easy to use.)
If you get really desperate, feel free to e-mail me directly at firstname.lastname@example.org. Just don't expect an immediate reply, especially on more complex questions. There's a reason I have gigabyte of e-mail, and most days I'm not able to keep up.
Michael lists some spots where you can find the Microsoft BDD members. Where do we hang out (virtually