To Redirect traffic from port 80 (http) to port 8080 (tomcat) use the following:

iptables -t nat -I PREROUTING --src 0/0 --dst YOURIPADDRESS  -p tcp --dport 80 -j REDIRECT --to-ports 8080

iptables -t nat -I OUTPUT --src 0/0 --dst YOURIPADDRESS  -p tcp --dport 80 -j REDIRECT --to-ports 8080