Network configuration.

Good day.
I appeal to the community for help.
We in the Center of additional education carry out the Internet. There will be an internal network + access through a plate + ADSL.
Questions to the hall:
1. How to control traffic?
2. How can the resulting network be used except for simple web access?
3. In general, how to organize such networks?
Solutions are welcome for both Win and Nix.
More than sure, this question is not new, and pretty wiped out. Perhaps you will say that therefore the issue is better not to torment Habr, but to Googl. BUT I would like to know ready, tested solutions. In our rural area there are not even paid specialists on this issue.
I wrote sensing a deep inner protest - it is easy to feel smart, it is important to inflate the cheeks and make a significant facial expression, it is more difficult to acknowledge their incompetence. And this is another reason to write. Habr gives a sense of personal contact. And this is a good vaccination against pride.
Thanks in advance to all.