|Try searching "internet cafe software" You'll find that produces a lot of links and then all you have to do is start reading and comparing.|
With regard to network setup. It's as basic as it can get, one 30+ host LAN. You'll want a NAT box of some sort (ie: SOHO Router, server) between your LAN and the internet and a firewall would be a good idea as well.
For 30 clients I'd recommend you buy a good unmanaged 48 port switch to connect them to. Your switch would in turn connect to your SOHO router (assuming you decided to go that route) and the router to the internet.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.