Steveb's most recent exec mail pours out roadmap info and special customer love for medium business (50-250 PCs). You can grab the exec mail RSS feed here.
Steve and Bill are speaking this week at the Business Summit 2005, read their stuff here. If I can find a blogger posting from the summit I will post their link here.
The exec mail give some announcement details about Centro:
"In July, we launched the Windows Server System for Midsize Business promotion that includes Microsoft Windows Server, Microsoft Exchange Server, and Microsoft Operations Manager Workgroup Edition, all under a single umbrella with attractive pricing specific to midsize organizations. Along with the next version of Windows Server, we will launch a new integrated product, code-named "Centro," that brings together Windows Server, next-generation Exchange and security technologies, and a new integrated management experience designed for the IT professional in a midsize business. "
It also announces the launch of http://www.microsoft.com/midsizebusiness/default.mspx.
Looks like they are launching the IT Capabilties assesment this week as part of the summit as well, the summit page says: