You certainly don't want to use ICS!!
Seriously, you're starting an internet cafe with no knowledge of networking?! You'll need (as a minimum) five client machines that work well (too slow and they'll go elsewhere), an 8-port switch, a server (to control user sessions and permissions), proxy server software (to log what they do), a router/firewall (to protect you from outside and prevent them from doing things they shouldn't) and about 5 grand of microsoft licensing money for the software licenses. Run the lot on Windows NT (very cheap) or if you have to Windows 2000 (more modern, but more expensive). Try and use Windows NT Server rather than Windows 2000 Server because of its simplicity. All the control you want is built right in. Linux is a viable alternative, but certainly not for the desktops (user friendliness), and the server side will be harder to set up and maintain if you're not familiar with it.
This might sound complicated, but that's why its experienced networking people who tend to set up internet cafes.