Tin Whistle, also called "Penny Whistle" or "Irish Whistle" is a six-hole, end-blown flute. Versions of the penny whistle are found in many cultures around the world.- Category ID : 26328
A general site by Dale Wisely, the "Undisputed King of Internet Tin Whistle Journalism". Message board, newsletter archives, a tune of the month, whistle reviews, and information and links for both novice and experienced whistlers.
Overview of the tin whistle by Gerard Manning. Introduction to the instrument, resources, recordings, and purchasing information. This document is rather old, so purchasing information is well out of date.
Wikipedia article which gives a good introduction to the history and description of the tin whistle. A useful starting point for someone unfamiliar with the instrument.