W2k and 2003

Hi all,
I am starting to migrate our NT domain to windows 2000 domain. I just received the windows 2003 media and I am curious about installing windows 2000 as a DC, and then install windows 2003 on a different box as an additional DC on the domain. Do you see or have experienced any issues by having both OSes on the network? Besides that I should wait a little longer until MS comes up with the SP1 for 2003 !!. I want to install and configure windows 2003 on another box so I can become more familiar with it. At this point I don’t know how much different both Oses are, I am assuming that windows 2003 has an XP interface and probably better migration tools the windows 2000 server. Any help is really appreciated. Thank you