I recently setup a linux machine as a server on my network. it has 2 network cards one is for the dsl modem the other is for my home network. if i enable both cards i lose access to the internet on all machines but if i enble just the card on my dsl modem it comes back to the servoer comp only. i would like so help on how to set it up to sharing the connection all over my network

You have to turn on IP-forwarding.

I've set up on a RedHat Linux forwarding firewall. The steps to archieve the forwarding are the following:

1/ Make a kernel that supports IP-forwarding.
2/ echo "1" > /proc/sys/net/ipv4/ip_forward.
3/ Use the package ipchains and execute the following commands:

ipchains -P forward DENY
ipchains -A forward -s 192.168.2.0/24 -j MASQ

192.168.2. is your internal network (netmask 255.255.255.0). Keep in mind that if you choose another netmask, you also have to change the 24 to something else.

You should also check some HOWTO's on firewalling. They give a very good explanation on this.