http://blogs.technet.com/rp/ Go behind the scenes with the team building the world's easiest small business phone system.
http://blogs.technet.com/sbs The official blog for Windows Small Business Server (SBS) support and product group communications.
http://communicationsserverteam.com/default.aspx The Microsoft Office Communications Server (OCS) Team Blog.
http://communicatorteam.com/default.aspx The Microsoft Office Communicator Team Blog.
http://telephonation.com/blog An independent information community driven portal dedicated to the subject of VoIP telephony over the internet in the small and medium business (SMB) area.
http://www.rptricks.com/blog Articles, how-tos, FAQs, tips and tricks, news, etc. for Microsoft Response Point.