Ok, I've been using Ubuntu for a number of months, and all of a sudden my computer stopped recognizing eth0. Eth1 (wireless) still works, but eth0 does not.

lspci | grep "Eth" shows:
"02:00.0 Ethernet controller: Intel Corporation 82573L Gigabit Ethernet Controller"

ifconfig -a shows only eth1, irda0, and lo.

sudo ifup eth0 shows:
"SIOCSIFADDR: No such device
eth0: ERROR while getting interface flags: No such device
eth0: ERROR while getting interface flags: No such device
Bind socket to interface: No such device
Failed to bring up eth0."

modprobe eth0 returns: FATAL: Module eth0 not found.

My /etc/network/interfaces file contains:
"auto lo
iface lo inet loopback

auto eth0
iface eth0 inet dhcp

auto eth1
iface eth1 inet dhcp"

My /etc/iftab file contains:
"eth0 mac 00:15:58:2e:06:f8 arp 1
eth1 mac 00:13:02:ad:5b:59 arp 1"
And the mac address for eth0 is correct according to my BIOS.

What happened and how can I fix this?

Did you try sudo modprobe forcedeth?

Don't think there is a module "eth0"

Well, I did that but nothing happened. Still not showing up in ifconfig -a and I can't bring it up with ifup. Is that the correct module I should be loading even?