About Gateway to internet

Hi Im using Fritz Card usb v2.0 on Suse 8.0 with kernel 2.4.18-4GB. I m connecting to internet with 128K using multilink option change kernel conf. Now I want it be gateway to internet. What must I do? Note: I have tried iptables command like below but I have don't succesfull. echo "1">/proc/sys/net/ipv4/ip_forward iptables -F modprobe ip_tables modprobe ip_conntrack modprobe ip_conntrack_ftp insmod ip_nat_ftp iptables -t nat -A POSTROUTING -j MASQUERADE