If you need some guidance and encouragement, in the Salt Lake Valley, the University of Utah offers ski conditioning classes that are taught through the orthopedic center. Friends who have participated in these classes have commented on their effectiveness and the quality of the instructors. Their web page also has ski-related articles and tips.
Ski Utah's fitness blogger Active Alyssa has an article with a focus on using a Bosu ball. She has photos and instructions for these basic exercises that will give your lower body a good workout.
Budget some training time and you'll enjoy that first day of skiing!