'Snort', and 'Who In The World'

Snort

Open source network intrusion prevention system, capable of performing real-time traffic analysis and packet logging on IP networks. It can perform protocol analysis, content searching/matching and can be used to detect a variety of attacks and probes, such as buffer overflows, stealth port scans, CGI attacks, SMB probes, OS fingerprinting attempts, and much more.

http://www.snort.org/pub-bin/snortnews.cgi

Who In The World

Given an IP address or host name, this software will do a WhoIs lookup and displays the originating country of the address. Will also display the WhoIs query details as returned by the server.

http://www.rotebetasoftware.com