OSX Server Data Migration to 2k3 Server

I have the pleasure of having the sole responsibility of being everything from Level I phone support on up to the CIO of a 400-ish user school network. Recently I made the decision to completely revamp the network and to basically oust the OSX Server that was the bane of my existence. However, this leaves me with the task of migrating a large amount of data (with file permissions and all) over to the new Win 2k3 server. I considered just sticking crossover cable between the two and essentially dragging and dropping but I am not at all certain if this is the best method or if it would even work. Any help would be greatly appreciated!
Thanks,
Dave Brock