Here's the thing:
I have two real ip adresses:
The first one I use for the firewall (iptables+MASQ) ...
All the private ip addresses (192.168.0.0) are being masqueraded through the first real ip address.
But I have second real ip address ... I want it to use it with a bridge so a computer from the internal network can use this address ...

Is that scenario possible?

If it is ... then how should I do it ?

Thanks in advance ....

Offhand, I don't see any reason why it wouldn't work. (then again, it's late and I'm tired so...). You'll just need to be sure to set the routing tables correctly to make sure that all data to/from the second real IP is passed through the firewall machine (since it is directly connected to your ISP). You might want to buy a third NIC for the firewall and just connect the NIC with the 2nd real IP to it via a crossover cable so you can route all traffic to/from that IP through a separate interface -- might make things a little easier.