Linux host, load balancing to 2 routers

I have a Redhat Linux server with 2 Ethernet cards connected to the same
network. (192.168.1.51) and (192.1681.52)

I also have 2 routers (192.168.1.1) and (192.168.1.2) each with a ADSL
connection.

I would like to have email routed over the first router using sendmail and
web traffic over the 2nd router using a squid proxy server .

Each service runs on the 1 host.

What do I need to configure to do this (ipforwarding, ipchains, route
default gateways, sendmail or squid settings)?

This is primarily for load balancing the server and getting the most use out
of the two connections

Thanks