Ah, finally someone with the opposite opinion :-)
Interesting thoughts, ATP_Al. I suppose as long as you make it clear in your cover letter that you are just putting your name out there and when you will be available, it can't do much harm. Sure, most of the time it will go straight to the bin, but I doubt airlines keep a list of "Do not hire - applied too early" candidates.
By the way, if anybody reading this wants to volunteer to review my CV, I'd really appreciate. I am NOT trying to get anyone to forward my CV to any employers! It's just my first aviation CV and I want to get it right.
Thanks!