monitoring bandwidth based on user accounts?

[warz]

i'm researching bandwidth monitoring options. i'm looking for a solution that could easily be implemented into a script, so nothing graphical. i've come across ntop, but i'm not sure if will do what i want the way i want. there's also a /usr/dev/net or something, that has some info in it. does anyone have any idea how web control panels, such as cpanel or interworx monitor their clients' bandwidth?

edit: ive also been looking into iptables. i know it can do this easily based on ip addresses, but im not sure if it can do it for user accounts on one machine.

[mynameistmp]

http://www.nufw.org/

[warz]

you're the master.

[Joe]

It's not unsafe for work. ^_^