<<
Is it possible to have 2 Nic cards in the same PC with different IP addresses? >>
Under some operating systems (i.e. Linux) it is even possible for the same NIC to have more than one IP address which is called IP aliasing. This can be useful if you have multiple IP addresses assigned from your ISP and you have more computers than that on your LAN and use a private network (i.e. 10.x.x.x).
Having multiple network cards in the same machine is called multi-homing. One has to be careful if one combines routers and multiple multi-homed machines in order to avoid creating routing loops. Some OSes turn on forwarding by default, others do not.
Arkitech, also if it starts annoying you that you have to have the multi-homed machine on for the second machine to access the net you can look into a hardware solution. Netgear makes a good cable/DSL router RT311 and one with a 4 port switch to make a router/switch the RT314. Linksys also makes the BEFSR router(/switch(/USB)) series of products that have won many awards. I'm personally a Netgear person though. To each their own. Cisco and others also makes very expensive solutions to the issue.
