What is my IP? - Find out what your IP is. Do not hesitate to open wimip.
GRC Port Scan - GRC Internet Security Port Scanner. Tests for open ports on your external IP address.
geoiplookup.net - (IPv4 only) Online tool to get accurate IP address information
Geo IP Tool - Find a geolocation of an IP address including latitude, longitude, city, region and country.
TrueIP - TrueIP is a small program that runs in the system tray, monitoring your IP address(es).
IPv6 test - IPv6-test.