Quite a few welding books on amazon, a few cover tig, and there are reviews on there to let you know what other people think.
Video wise, the only ones I've found have been specialised, regarding pipework, and they covered stoving as well, so not really what your looking for.
Some interesting things turn up on youtube once in a while, there are some vids on there of a few ali butt welds with a new machine and they show the technique quite well.
Thanks for reply Hugh, I would prefer a dvd or video but if I cant find one I will have a look on Amazon at books and reviews.
How do you go about finding something about welding on youtube ?