I have a gaming network with 10 terminals and my server running Slackware 10. Is there a way to make my gaming network available online? Or make available to friends to log in and play from they're PC in other countries?

You could use port forwarding of the game server or allow them to connect using VPN (you would need to port forward the VPN ports).

Port forwarding assuming you're using a router for your local internet.

It's a gambling network. The terminals are slot machines and the server is the cashier. I'd like it if people could play the slots from they're windows pc or android tablets. It would be great if users could login to the terminals via the web to play the slots.

Well details matter. You require an implementation far more complicated than I have time to advise at the moment. In order for others to effectively help you; you have to provide a lot more technical details then you have already. "Gaming" or "Gambling" terminals isn't very descriptive as most online gambling I've seen is written in either Adobe Flash or Java.

Elaborate on technical details so others may help you.

e.g. what language is the server/clients written in? Is it a custom system or did you purchase a closed source product? The protocols used to communicate? etc. In all likely hood you will still need to port forward to allow external clients to connect to the server (if you require installable clients on your gamblers' machines) or a custom web client would need implemented.

SAM