@lsf:
If this is for home use, i'd say, set up encryption on the AP (WPA prefered) then treat the zone as if it WAN. Add pptp to it in order for yourself/kids to use the internal LAN. (if you set up rules for some ip's (you, your kids etc.) you have basically opened up the network anyways. So, WPA or WEP on AP, PPTP to reach lan, and deny any acess from WLAN other then what you would normally allow on WAN.
Set it up today and it is working like a charm. Way cool. pfsense rocks. 8)