Vote for netfee for isa server
Integrated with popular firewall systems (ISA server etc.), Netfee can do Usage Analysis, Reporting, and Performance management. It is a network software solution for managing Internet access.It consists of a Analysis module, charge module and reporting module.
Netfee analyzes the firewall's log files, then writes the result into database. The administrator can monitor the Internet useage (Bytes,Time,URLs etc ) of every user in realtime by querying the database. And based on the usage of Bytes and time, Netfee can calculate the user's fee to pay.