Fedora Networking :: NAT Setup - Activated Eth0 Does Not Work

I've a desktop running Fedora 10 connected to the Internet via LAN. There's 3 network controllers in the desktop. One integrated to the motherboard and two additional. I would like to connect other computers (two laptops, one running fc9 and the other Window$ XP) to the Internet via the desktop. I googled the question and found out that I need to adjust thing called 'NAT'.

For that purpose I did the following:
iptables -t nat -A POSTROUTING -s 192.168.2.0/24 -j SNAT --to-source 192.168.*.*
where 192.168.*.* - is desktop' IP address. I want to use 192.168.2.0/24 as a network for laptops. I activated one of devices (eth1), gave it IP address:
ifconfig eth1 192.168.2.0/24
and connected f9 laptop to it.

On the laptop I activated eth0 with the same IP. The problem is: it doesn't work. I can't ping anything from the laptop except its own address (192.168.2.0).