Check the HOWTO... 

Forum: PCMCIA Network Adapter Issues
Re: eth0 won't initialise on bootup. (James Bramich)
Date: 1999, Nov 22
From: David Hinds <dhinds@pcmcia.sourceforge.org>

The section on Red Hat describes how you need to set up /etc/pcmcia/network.opts so that the Red Hat network control scripts will work automatically. -- Dave