I have an old WAP11 from Linksys that I'll use as an example.
There are two ways to administer it, One with Windows based software, the other by pointing your webbrowser to it's IP address. (In my case I've changed it to 192.168.2.1)
Some of the available options are:
WEP encryption
MAC address verification
DHCP server administration and setup.
Port forwarding and blocking
If I go into the DHCP server admin, I see the following options:
DHCP enable
DHCP IP range
I don't use the dhcp services on mine, but didn't want to shut them off completley. I enabled it, and set the range to 192.168.3.1-5 (this requires other setup on your network we wont cover here, but is a good example). I also want to have info written to a logfile, so the IP 192.168.2.255 is nothign but an HTML page that holds the error log from the device. So the way it sets, any machine that has a static IP that isn't 192.168.3.1 thru 192.168.3.5 can connecft to this station by using the SSID.
Friend has a protable device (HP Jornada I think) with a wifi card. He can pick a hardware setting for my house that sets up his wifi card as so:
SSID = '[x128x]ladybelle' (the [x128x] is a quick symbol that means wep is on, and ladybelle is my coonhound's name)
IP address 192.168.3.101(subnet and gateway etc are also defined, but not important here.)
WEP_Enable = true
Default_KEY_broadcast = 0
Key = xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx
He is using WinCe so all this is in an ini file somewhere, let him fight with that winCE shit
The point is he is connecting without using dhcp.
I'll poke around a bit, but the situation you describe is going to need either pre-configured network set-ups on the wifi enabled devices (like the one I describe above) or a seperate subnet with a second dhcp server (which is prolly the default setup on the wap). either way is fairly simple to setup.