Inplace Domain controller upgrade from windows 2003 EE + SP1 to windows 2008 Entp

hi,

need your inputs on domain controller upgrade pre and post tasks

my set-up has PDC and has windows 2003 EE with SP1 installed and ADC with windows 2008 Entp.
Exchange server 2003 with SP2.

so can you please give me standard guide lines or checklist so everything should happen smoothly.