I've been going through the archives and am hoping someone can set me 
straight here.

This is my network setup:

WAN/DSL (sis0) --- LAN (sis1 - 192.168.154.0)
                      | 
                      |  DMZ/OPT1 (sis2/vlan1 - 192.168.155.0)
                      |
                      -- WLAN Private/OPT2 (sis2/vlan2)


Basically I've got a 3com AP with multiple SSID's that supports vlans. 
The WAN link is nat'd on DSL. I have an open SSID using the DMZ. It is 
isolated with certain holes punched through to the LAN but unrestricted 
NAT traffic out through the WAN. I would like to now bridge OPT2 with 
the LAN because the new vlan uses an SSID using WPA2 etc. So I would 
like unrestricted access between the LAN and OPT2 and OPT2 and the WAN 
interface. If I set up a rule for OPT2 to have access to anywhere then 
it will go out through the WAN but can not contact anything on the LAN. 
I thought with bridging I didn't have to set up any additional firewall 
rules.

I don't have bridge filtering on but it seems that without firewall 
rules for OPT2, no traffic goes anywhere.

A revised diagram would look like this:

WAN/DSL (sis0) --- LAN (sis1 - 192.168.154.0) -(bridged)- WLAN 
Private/OPT2 (sis2/vlan2)
                      | 
                      |  DMZ/OPT1 (sis2/vlan1 - 192.168.155.0)
                     

Forgive me if my explanation doesn't make sense, I'll try to clarify if 
I can.