@@Situation:
@@2 Lans: LanA and LanB;
@@LanA: internal IP classes: 192.168.2.0/24; 192.168.3.0/24
@@      metropolitan IP: AAA.AAA.AAA.AAA
@@      Internet IP: XXX.XXX.XXX.XXX
@@	Gateway for Internet: YYY.YYY.YYY.YYY

@@LanB: internal IP class: 192.168.5.0/24
@@	metropolitan IP: BBB.BBB.BBB.BBB

#And now, the setup:
##Router from LanA
ip tunnel add netb mode gre remote BBB.BBB.BBB.BBB local AAA.AAA.AAA.AAA ttl 255
ip link set netb up
ip addr add 192.168.50.2 dev netb
route add -net 192.168.5.0/24 dev netb

##Router from LanB
ip tunnel add netb mode gre remote AAA.AAA.AAA.AAA local BBB.BBB.BBB.BBB ttl 255
ip link set netb up
ip addr add 192.168.50.1 dev netb
route add -net 192.168.2.0/24 dev netb
route add -net 192.168.3.0/24 dev netb

@@And now, the routing tables:
##LanA router
#Destination   Gateway         Interface
192.168.2.0    0.0.0.0         dev eth1
192.168.3.0    0.0.0.0         dev eth1
192.168.5.0    0.0.0.0         dev netb
192.168.50.0   0.0.0.0         dev netb
AAA.AAA.AAA.0  Metro GW        dev eth2
XXX.XXX.XXX.0  0.0.0.0         dev eth0
0.0.0.0        YYY.YYY.YYY.YYY dev eth0

##LanB router
#Destination   Gateway         Interface
192.168.2.0    0.0.0.0         dev netb
192.168.3.0    0.0.0.0         dev netb
192.168.5.0    0.0.0.0         dev eth1
192.168.50.0   0.0.0.0         dev netb
BBB.BBB.BBB.0  0.0.0.0         dev eth0
0.0.0.0        Metro GW        dev eth0

@@ QUESTION:
@@ Using this setup, LanA and LanB can ping eachother and cand transfer various data between lan pc's. But what must I do for computers from LanB to be connected to the internet using the router from LanA? Any sugestions are apreciated =)