"First Priority is to get a whistle that WORKS !"

The oak brand of D whistle is a nice one. I've played the pennywhistle for seven years. I started on an oak and a generation. The generation sounded horrible, but the oak (which is the same style of cheap whistle) sounded great, and I've never gotten a more expensive one.

For easy tunes, I suggest "Mari's Wedding," "Skye Boat Song," "Britches full of Stitches," "Tell me Ma Polka," "Road to Boston," and "Scotland the Brave," in addition to many of those mentioned here. Mel Bay's tinwhistle book is a good resource. I don't know if these are common tunes at sessions around you, but I've heard most of them played at least once while out contra-dancing.

To clear the water out of your whistle, you should place your thumb over the hole on the mouthpiece and blow as hard as you can. (No sound should come out when your thumb is over the mouthpiece.)