http://sniff.numachi.com/ is Yet Another Digital Tradition, a mirror of our own Digital Tradition Folk Song Database which cleverly converts our tunes in to a number of different notation formats.

This Google Search (click) will lead you to lots of interesting sourses of tin whistle tab.

There's a Mudcatter named Pavane who has created a program called Harmony that does all sorts of things - but I can't figure out whether it does tinwhistle tab.

-Joe-