Looking for a simple, powerful solution for real-time monitoring of user activity.

Our user experience sometimes slows to a painful crawl. ISP says that all traffic goes to/from a single private IP--naturally, the BMgr 3.9 box. They tell me that I'm using nearly all my avail. bandwidth, and that I need to check to see if users are streaming, file-sharing, etc.

No way for me to check that in real time as currently configured. Anyone have a cool tool that you really love that you'd care to share? Even better would be to *find* that Joe Blow is using limewire and be able to kill that connection :), but would settle for knowing which IP is currently pulling 80% of my throughput.

Thanks for any ideas,