cocoa packet analyzer

It is a native Mac OS X implementation of a network protocol analyzer.

Packet analyzer with HTTP file capture and a neat Graphical Packets Mode. Free.

Sniffer80 is simple web sniffer and packet analyzer based on .NET technology.

hping is a command-line oriented TCP/IP packet assembler/analyzer

oriented TCP/IP packet assembler/analyzer

Network Sniffer is a Windows based Packet sniffer an Network analyzer