Sharing internet connection

[fivezerosixzero]

I want to share my connection from one computer to two or three others (possibly more in the future?).

Here's my setup as of now:

-Wireless router inside house
-Wireless NIC inside my room

Could I turn a spare PC into something that would share it's internet connection.

My knowledge on this subject is limited, so I was thinking something like this:

Wireless router -> Spare PC -> One NIC -> Router/Switch/Something -> Multiple PC's
Or
Wireless router -> Spare PC -> Multiple NIC -> Multiple PC's

So, which is the best approach, or is there another approach which would work better?

Also, could someone point me in the right direction (a tutorial, or something) on which programs I would need and how to configure them for this setup?

I've tried searching Google and the forums, but I don't know what keywords I should be searching for. (routing, sharing internet connection, I've tried many things)

If more information is needed about my setup then ask.

Thank you in advance.

[edudlive]

Wireless router in house - to Wireless NIC on spare PC - shared connection from wireless NIC to NIC - hook hub/switch up to regular NIC, g00t

[fivezerosixzero]

Thanks for the advice. Does anyone have any more to give?