Have you read this:
http://doc.pfsense.org/index.php/Interface_Bridges
Not much there though. You shouldn't need to select static/dhcp etc for bridged interfaces, they will all take their values from the interface you're bridging to.
Steve
Edit:
You could read through this thread as well.
Edit: Hmm, I going to have to play around with this but from reading through this stuff it seems you have to:
Create a bridge interface, br0. (you'll need to assign at least one interface to it)
Assign br0 to be LAN.
Add other interfaces to the bridge.
This seems to be causing much confusion and I can why since it seems more logical to create a bridge and then add the lan interface to it. I'll be very interested to see how this works out for you.