updated modprobe can't locate device eth0

Hey, I have been trying to upgrade my kernel from RH9 install kernel
2.4.20-8 to 2.6.14.

I got most of the important stuff working, but i have yet to get eth0
up and running. I upgraded module-init-tools to 3.2-pre9, and ran
/sbin/generate-modprobe.conf > /etc/modprobe.conf, since i read that
the new version no longer uses modules.conf.

it contains:

alias eth0 8139too

and

install eth0 /bin/true

but if i boot up the old kernel (2.4.20-8), it says something like
'device eth0 does not appear to be present, delaying initializaiton...'

and if i try a /sbin/modprobe eth0, i get 'device eth0 can't be
located'.

now /sbin/modprobe 8139too loads the module and enables the ethernet
device, so why does is the alias not recognized?

Thanks for any clerification