Not sure I understand the question.
You own the AP and have all the keys, passphrases, etc... and don't know the IP range in use?? Easiest way, if you own the AP, is to login and check what is in use. Most will probably be on the default range of 192.168.1.100 and up. that's for linksys at least.
If you want to sniff the network for addresses in use then you are limited with wireless nics on windows. For sniffing you cannot place the card into passive/promisc mode unless you get the airpcap drivers from CACE.
You could just run wireshark and wait for any broadcast traffic to hit the wireless nic..
alternatively, run linux and use Kismet.
or start guessing.
dean
Dean, to answer your question, I
do know what subnet
I'm on... I'm trying to "crack" my own network as an experiment. As it sits, I'm simulating that I've been able to connect to the wireless network with the SSID/pass-key, but am unable to figure out a way to figure out the subnet being used, without having an IP on the interface that I would be "sniffing" with find find said subnet... hope that clears things up a little.
I'll check out Languard, as I've never heard of it. Maybe it's the answer! Thanks for the replies guys!