libvirt: virtual lans and virt-install command with two nics?

[Andy Graybeal]

first off, how do i do a virt-install with two nics?

i'm on ubuntu 10.04.

here's my command with one nic:

sudo virt-install         --connect=qemu:///system 
--name=pfsense         --ram=512 
--file=/srv/vm/pfsense/pfsense.qcow2         --file-size=5 
--network=bridge:br0         --accelerate 
--cdrom=/srv/Desktop/Tech/Software/os/pfSense-1.2.3-RELEASE-LiveCD-Installer.iso.gz 
       --hvm         --vnc

i don't understand the virt-install manpage enough to figure out how to 
do multiple nics.

also i don't grasp how to create vlans in virsh.  i understand that 
net-define points to network definition .xml file, but i can't find any 
of the files in my /usr/share/libvirt folder.  where does the 
default.xml (default network) live?

i also understand that net-create create the .xml file...
can i see some net-create examples?

-andy