Server and Exchange Upgrade

I am doing an upgrade on the server. The current server is Win2k with Exchange 2k as well. I have the new server running with 2003 and am adding Exchange 2003 as well. The Exchange 2k is in native mode and I am not sure if I should install 2003 in native or mixed mode? The new server is replacing the old one when it is fully functional so they will not co-exist for long, I just need to be able to transfer files from one to the other. Then the old one comes out.

I also need a way to transfer exchange email from the old server to the new. Everything that I have found about transfering will not transfer half the stuff that people are using (rules, calendar, ect) Anyone know of a good way?

Thanks