It seems that when using the intel proset drivers (v12.2, I believe) with one of their server cards (PRO/1000 MT Dual Port), under Windows 2003 Service Pack 2, it isn't possible to get into the tabs for advanced properties, e.g. Teaming, et al.
This makes setting up teamed network cards (and ultimately a multicast NLB cluster on top of these) quite tricky.
Bugger. Time to talk to Intel!