Recently I purchased a Desktop with Atheros AR8151 Gigabit Ethernet chip. I normally use Slackware. When I googled for drivers for this chip, I found very few usable answers.
Actually, Slackware 13.0 already has a driver for this chip in the Kernel. The device name is: atheros_eth. Only thing that the boot process does not do is to put the following line in the /etc/modules.conf file:
alias eth0 atheros_eth

dmesg reports the chip as:
Atheros(R) AR8121/AR8113/AR8114/AR8131/AR8132/AR8152 PCI-E Ethernet Network Driver - version 1.0.1.14
Copyright (c) 2007 - 2009 Atheros Corporation.
atheros_eth 0000:02:00.0: PCI INT A -> GSI 18 (level, low) -> IRQ 18
atheros_eth 0000:02:00.0: setting latency timer to 64

So, the steps to activate this chip are:
1. put the alias line in /etc/modules.conf
2. ifconfig eth0 192.168.1.123 (e.g.)
3. You should have also configured /etc/rc.d/rc.inet1.conf file.
4. If you are using DHCP then(2) is not necessary.

I hope this helps!