only if you can figure a way to install a packet sniffer on a router.
you could also get a linux box set up and install nagios
http://www.nagios.org/ and snort
http://www.snort.org/about.html
if you set the linux box up as a firewall between your hub and your internet you should be able to do quite a good job with these two applications.
I do recommend the clamwin on each computer in the network.