OS 10.4 - Internet sharing: doing it the proper way

Hello, first post...

I would like to set up my iMac Core 2 Duo (10.4.10) for internet sharing. It is connected wirelessly to my home Wi-Fi network, and is the only computer in my home office which currently has an internet connection. I would like to be able to connect some non-wireless PCs to the internet, using the iMac as bridge. I've seen all those dire warnings about the potential for messing up neighbors' IPs, getting my internet service cut off, etc, if things are not set up correctly. So I was wondering if someone could give me some advice or point me to a good tutorial or just more info on how to properly and safely configure internet sharing, without screwing everyone else in the neighborhood.

(sorry if this has been posted before)

Thanks