I started to play around with Exchange 2007 on my windows 2003/2008 domain. As my Windows Server 2003 DC had Exchange 2003 installed I thought I would try installing Exchange 2007 on the Windows Server 2008 DC.
I Managed to get the install under way with little problem.
I started to write a How To guide for the migration process but I found a very good guide on the web on www.msexchange.org.
This guide I found very useful although I can fumble my way round the exchange system it was handy to have some sort of guide line to follow. IT also mentions about public folders and how to set up the replica's and so on.
Here are the links to the 3 part guide on transition from Exchange 2000/2003 to Exchange 2007.
Once I completed part 3 I was left with a Windows Server 2003 DC that I no longer need. SO the next thing in my testing is to Transfer/Seize the FSMO roles onto my Windows Server 2008 DC and then demoting the Windows Server 2003 DC.