The Open Directory is a community effort to build the world's largest human-edited Web directory. The tin whistle category was pretty badly out of date, so I volunteered to edit it, and my application was accepted yesterday. I've just started working, and it will take me a while to get everything in order, but I have managed to go through the backlog of submissions and publish those which fit the category. (Note that if you're an instrument builder I've published your link in the Tin Whistle/Makers category and if you run a store then you should be listed in /Shopping/Music/Instruments/Winds/Tin Whistle/, which I don't control.)
But this is just a start. My goal is to build the most comprehensive index of tin whistle links on the Internet, and you can help! There are many sites I haven't had a chance to look up and add, and more I'm simply unaware of. Do you know of a whistle-related site not currently listed? General sites, links to instrument makers, tune lists, and performers are all fair game. Find the appropriate category and use the "suggest URL" link at the top of the page to let me know. I want to build a useful resource for the tin whistle community.
Note that it takes a few days after I've added a site for it to become visible to the public, so please have patience after you submit.