If you are looking for article on how to migrate your aging Exchange Server 2003 to Exchange 2010, here's one to read written by Michael Smith for Windows IT Pro website.

This is also my project to upgrade our Exchange Server 2003 to Exchange Server 2010. I will share my experience and update this article.

Windows IT Pro. Migrating from Exchange Server 2003 to Exchange Server 2010: A Small Organization Perspective. Retrieved August 18, 2010 from http://www.windowsitpro.com/print/exchange-server/Migrating-from-Exchange-Server-2003-to-Exchange-Server-2010-A-Small-Organization-Perspective.aspx