Upgrading/Migrating Windows 2000 Server & Exchange Server 200 to windows 2003 Server

I will note first the current configuration.
(a) 1 x Windows 2000 Server Standard (File Server), Domain Controller, (LAN)
(b) 1 x Windows 2000 Server Standard (Mail Server), Domain Controller, Exchange Server 2003, (LAN)
(c) 1 x Windows 2003 Enterprise Server, running Citrix Presentation Server 4, (LAN)
(d) 1 x Windows 2000 Server, running Surf Control, (LAN)
(e) 1 x Windows 2000 Server, WEB Server, (DMZ)
(f) 1 x Windows 2003 Server, Citrix Secure Gateway-Web Interface (DMZ)

I have two new servers to replace (a) & (b)
I am installing Windows 2003 Server Standard on the two new servers.

What is the easiest and best way to migrate to profiles & e-mail from the old servers to the new servers ?