What is my IP? - Find out what your IP is. Do not hesitate to open wimip.
HostedScan.com - Online vulnerability scanner for servers, networks, and web applications.
geoiplookup.net - (IPv4 only) Online tool to get accurate IP address information
HackerTarget.com - Security Vulnerability Scanning based on Open Source Tools.
TrueIP - TrueIP is a small program that runs in the system tray, monitoring your IP address(es).
Intruder - Intruder is a security monitoring platform for internet-facing systems.