1) Start them young as possible providing they leave the hill wanting to come back for more. No super cold days, don't tire them out, etc. Our youngest was on the chairlift before his third birthday, but after two or three runs he would tire.
2) I started this post a year ago to help others save money: http://www.epicski.com/forum/thread/92869/money-time-saving-tips-for-parents-with-small-children-who-ski Please add to it!
3) Don't worry too much if they sit back a bit at a super young age. Kids will get stronger and forward in due time.
4) Use a harness (for safety) to help toddlers get on the higher or faster chairlifts. Doing 30-40 lb. curls is no big deal when the kid belongs to you.
5) Boots are the most important piece of equipment. Toddlers just need comfort and warmth. But when they start carving, find a better performing boot and their skills will improve faster. Lange has a great series that gets stiffer and stiffer as the kids grow.
Below is a photo taken a few years ago when the kids were 4 and 6. The older child was already skiing most black diamonds (only a few per day so he wouldn't tire). The little guy has better natural balance, but wasn't as strong (his brother loves martial arts). The biggest problem the day this photo was taken was an emergency bathroom break, which is why we were heading behind some trees.
Edited by quant2325 - 5/4/11 at 11:34pm