Windows Small Business Server Migration
http://technet.microsoft.com/en-us/sbs/gg981878
Migration from SBS2003 to EX2K3:
http://www.msexchange.org/tutorials/migrating-small-business-server-2003-exchange-standard-part1.html
Migration SBS2003 to EX2K10 (Windows Server 2008):
http://www.experts-exchange.com/Software/Server_Software/Email_Servers/Exchange/A_2881-Migrate-Small-Business-Server-2003-to-Exchange-2010-and-Windows-2008-R2.html