1. enable CONF_BRIDGE=1 in main.cfg
2. in file bridge set BR_IFS= - list of interfaces that should be added to bridge
        example: BR_IFS="eth1 wlan0"
3. in file interfaces set INTERFACES= you have to remove from list interfaces that should be
   added to bridge AND add interface br0
        example: INTERFACES="eth0 br0"
4. edit file ifcfg/br0 (create new) and add this lines:
        IP_ADDR="_ip_address_of_bridge"
        PREFIX="24"
   example:
        IP_ADDR="192.168.3.254"
        PREFIX="24"
5. save config to flash using "wrunt" command
6. reboot AP

file: bridge
	BR_IFS="eth1 wlan0"
file: interfaces
	INTERFACES="br0"
file: main.cfg
	CONF_BRIDGE="1"
	CONF_NAT="1"
	CONF_DHCPD_ETH0="0"
	CONF_DHCPD_ETH1="0"
	CONF_DHCPD_WLAN0="0"
	CONF_DHCPD_BR0="1"
	CONF_DHCPC_ETH0="1"
file: nat
	NAT_IF="eth0"
file: ifcfg/br0
	IP_ADDR="192.168.3.254"
	PREFIX="24"


"wrunt" 
"reload" - should work ... :)