Simple routing, netork basics

[Florian Hengstberger]

Hi!
In a few days I'll get fast access to the internet via WLAN.
I have a wireless accesspoint connected to my (single) network card.
I have one single public static IP address from my ISP and
I'll assign it to this card.
Of course I want to give other people in my LAN also access
to the net, so I'll by a second network card, setting it up with
a local ip-address/netmask.

A few questions arise:

1) I'll have to do some routing with my computer, is there a good
online tutorial you can recommend covering this rather simple case?

2) What's the easiest way to log the traffic to my ISP?
I don't want to exceed a certain download/upload limit. 
How can I gain controll over this?

3) I have to network cards: you can I be sure that the right
IP is assigned to the right (physical) network card using rc.conf? 
I has to depend somehow on the position on the PCI-bus: 
which one is detected first and assigned first or 
due to which fact are the network-cards numbered?

Thanks a lot
Florian