The best way to get ready for tele turns is to make tele turns but, a little bit of exercise before (and in between) days on the hill will certainly help. If you really want to bust it out, ask me about the Tabata Protocol (and see the vids at iTunes U and the listing below)...
Bowdoin's coaches have posted training videos of many excercises that are excellent for skiing in the Strength & Training section of the Athletics page on Bowdoin's iTunes U (link launches iTunes): Training Videos
Check out these workouts from the August 2009 issue of Outside magazine, designed to build real world strength for outdoor athletes: "Build Power in Three Easy Steps"
Core and overall strength is the goal, so work in a good compliment of chest, shoulders, bi, tri, and back exercises, too. While calves, shins, hams, quads, gluts, lower back, and abs are focus muscles, we have to keep things balanced. Remember, for every quad exercise, you need to do a complimentary hamstring exercise; for every bi, a complimentary tri, etc. We want explosive power and stamina, too, so, mix it up. Low weight, high reps in one drill (or one day, etc.), higher weight, low reps another. And mix the drills up, too, day to day, week to week.
Of course, cardio is a must! Whether you cross train outdoors by running or cycling, or spin your wheels on a machine inside, it's important to get your heart rate up for a sustained period at least a couple times a week. (My favorite when indoors is the rowing machine; can't beat it.)
Here are a couple of other workouts to consider: