IP

Connected - The IP Protocol
Section 3 of "Connected: An Internet Encyclopedia" discusses datagrams and streams, subnetting, and the delivery model.
http://www.freesoft.org/CIE/Course/Section3/

Foundations of the Internet Protocol
ACM Crossroads magazine article explains network protocol concepts, IP packets, and IP addressing.
http://www.acm.org/crossroads/columns/connector/july2000.html

IP Performance Metrics Charter
IP Performance Metrics (IPPM) Working Group at IETF.
http://www.ietf.org/html.charters/ippm-charter.html

IP Self Test
This 18-question online quiz tests your knowledge of the nuts and bolts of Internet Protocol.
http://compnetworking.about.com/od/networkprotocolsip/l/aa081000a.htm

IPMI - IP Multicast Initiative
Forum to accelerate adoption of the IP Multicast Initiative through education and marketing.
http://www.ipmulticast.com

ipSwitchboard
Site tracks the IP address of computers on the Internet, particularly Web and FTP servers.
http://www.ipswitchboard.com/

IPTV News.net
Offers information and news on the evolving technologies of internet protocol television including hardware, software, and services.
http://www.iptvnews.net/

Museum of Broken Packets
Collection of broken, malformed, or peculiar packets found on the Internet, with theories as to how they came to be.
http://lcamtuf.coredump.cx/mobp/

MyWanIP
Free utility detects one's current IP address from behind a router.
http://www.mywanip.com/

RFC 791 - Internet Protocol
Request For Comments 791 documents the fundamental workings of IP.
http://tools.ietf.org/html/rfc791

What Is My IP Address?
Free service automatically determines one's address on the Internet.
http://whatismyipaddress.com/