Reinstalling Exchange roles on SBS 2008

http://technet.microsoft.com/en-us/library/dd728006(WS.10).aspx

http://blogs.technet.com/b/sbs/archive/2009/05/21/repair-microsoft-exchange-server-roles-on-windows-small-business-server-2008.aspx

http://technet.microsoft.com/en-us/library/dd767439(WS.10).aspx