Adding ethernet card to modprobe.conf

[Stephen More]

The install of FC2 went ok, except for 1 thing...It did not recognize
my ethernet card.
insmod 3c509 worked so I added and entry to /etc/modules.conf
alias eth0 3c509
rebooted and nothing happened.
I read that modules.conf is for kernel 2.4 and I need to make an entry
in modprobe.conf so I did:
alias eth0 3c509
I rebooted again and nothing happened.

What is the right way to add support for this network card ?