tcptrack -- Packet sniffer which displays TCP information like the 'top' command
http://www.rhythm.cx/~steve/devel/tcptrack/
tcptrack is a sniffer which displays information about TCP connections
it sees on a network interface. It passively watches for connections on
the network interface, keeps track of their state and displays a list of
connections in a manner similar to the unix 'top' command. It displays
source and destination addresses and ports, connection state, idle time,
and bandwidth usage.