>First, as I have been asked this a thousand times, is >there a difference between a fiddle and a violin?
Not really... it's mostly what you do with it. All else is window dressing :)
>Do fiddlers use alternate tunings? I understand that >the usual tuning is G-D-A-E. Why is this best?
I wouldn't rush into alternate tunings. Believe me, you'll be plenty busy with the regular one for a while. :)
>What pitfalls lurk for the beginner? I would rather >learn correctly than to have to re-learn later.
Er... I still consider myself pretty much in the beginner category, but one thing that is starting to haunt me is my left hand position. I can't help but "squeeze" the neck with ball of my first finger, and no matter what I do I can't manage to play without it. Bad habit, I hope, that I can eventually break -- I don't think I'll ever manage vibrato until I do.
>What other questions should I be asking that I haven't >even thought of yet?
Be careful finding a teacher who you can get along with. Some may push you harder than you'd like, or maybe you need to be pushed. So talk to lots of folks and keep looking until you find the right guy or gal.