We are planning on including cross-networking for DoF. However as the technology is quite new, we might run across too many problems and have to scrap that feature.
Xbox users will have slight advantages in places PCs don't.
For example, the Xbox User Interface is quite different from the PC, due to the limited amount of buttons you have to work with, as well as a less-precise control stick vs. a mouse. So we have developed a unique control scheme and a user interface that is unique to the Xbox version and will help players manage their armies much easier.
Xbox users also get benefits from having a version that is optimized to run on their system, which means no matter how many units you have on your screen, or what spells or actions are being cast, it wont lag or stall. This is just undoable on a PC, as everyone's PC is different and we cannot optimize it for them, changing settings on their own can make a game run smoother, but certain events can trigger signifigant drops in performance.
Also, Xbox users on average have a faster internet connection speed as well, as they are not bogged down by firewalls and other security measures that windows takes.