How To: Freehand Mount Ski Bindings from steve power on Vimeo.
I wouldn't recommend it unless you actually know what you're doing/don't care about your skis. If you have a jig, that makes it easier, or you could find the paper jig which would make it a little easier. But, like I said, I would really, really recommend just getting them mounted at a shop, unless you really know what you're doing or just really don't care about your equipment, because you CAN completely wreck your skis, or even hurt yourself.
The safest way (and the fastest, too) to mount bindings to your ski is using a drilling template. They aren't even very expensive, but hard to get. Each producer of bindings has his own mounting system. If you can acquire a drilling template for the marker, look/rossi etc. upper class bindings, you don't even have to "train" mounting bindings.
sry 4 double post, but i need to add, that im not talking about those self-sticking paper templates you get delivered with your bindings. Im talking about ISO-standardised drill templates marker etc. offers the tech shops. and thats why you should go there, because you probably won't be able to buy one.