Getting Gentoo up and running on a Dell 8600 Inspiron is fairly easy. But I had some initial problems with the network settings.
The problem was that the network card (Broadcom 4400) wasn’t detected. To fix this I simply had to execute.
> modprobe b44
But the tricky part was that I had to unplug the network cable (and then put it back) before I could start the eth0 interface.
> /etc/init.d/net.eth0 start
Except from this I just had to follow the installation instructions from Gentoo.