There are several factors to consider.
One - what dialect? Mandarin? Cantonese? Taiwanese?
Two - How will the person be learning? One-on-one? In a class? Home study (via tapes, etc?)?
Three - how adept is the eprson who wishes to learn? Does the person already speak other languages? Does learning come easily?
I would call the local college/communioty college and/or the nearest Chinese-American organization. I bet you can get all your questions answered between the two of them.
Good Luck!
diane