ICS is a great way to allow your networked PCs to share one internet connection. The main thing to know is
that the PC that is connected to the internet needs to be running at least Windows 98 Second Edition. The
other PCs on your network can be running any other version of Windows back to Win95.
Microsoft has the following pages available:
Microsoft also has a knowledge base article that explains how to troubleshoot ICS. It's packed with info:
If you're using ICS and you have an "always on" internet connection, I highly recommend that you install a firewall.
ZoneLabs has a good one called Zone Alarm, which is free for personal use:
Once you've got a firewall installed, you can use the "Shields UP" utility from Gibson Research Corporation to test your security: