It doesn't make a lot of sense to spend hundreds, thousands or tens of thousands of dollars on a season of skiing and racing and then start it unprepared. Dryland training is a must, especially in those 4-6 weeks when your skis are waxed, sharpened and you're waiting by the door but snow just doesn't want to come!
Here's a good collection of pre-season and dryland training exercises.
Harald Harb has this excellent series on training with a slant board.
Something as simple as doing squats on a balance board will be very helpful. Especially if you do them on one leg only (careful - it may be dangerous for the knee, if you don't know what you're doing). Make sure you at least warm up first!