LinuxQuestions.org - Help building an Internet Supplying Server (mini ISP)

Hello, i sorta need help with this project i decided to start. All i need is a helpful push in the right direction, as in, stuff i should know about to start it up, i really want to learn stuff along as i do this.

Here's a scenario; students living at a hostel are offered internet at various packages. Basically, what i'm trying to do, is equally divide the bandwidth of a DSL connection to students, but that's just the beginning.
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To keep track of which student paid for their connection, and which package they're on, i'll assign each student a login ID. Only the login ID's that have been paid for, will be allowed to access the internet.
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Say a computer logs onto the network and tries to open a website, it's served with a login page, only if the login is successful, is it allowed to go online. After the login is successful, the package type has to be determined.
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Package types will probably depend on timings, certain users will be allowed online at certain times. If they log on at a time not specified in their package, they'll be charged for data consumption.

Note: I know this is a long thing, and i'm willing to work on it, i have about a month to get this thing in workable condition, and i'm ready to learn stuff if i need to. I don't have much experience with Web Dev apart from a little HTML/CSS, but i understand a bit about how PHP works, and i understand the login page will need to work on PHP with a MySQL backend, i can learn that, it's the rest of the things i'm confused about.

I'm probably going to use Ubuntu Server 10.10.

Thanks in advance.
minigilani