The best way to learn on your bike is to find a deserted road way that is smooth and flat.(no pot holes either)
Start by getting to know where your bike lifts, ie start at about 4 or 5000 rpm, and pop the clutch but hold the throttle steady don't bang it open or you may flip the bike, don't pull on the handle bars either because you will have no control,let the engine work for you, you can also sit slightly further back in the seat this will aid you a lot.
If the wheel does lift, your first reaction is going to be to shut off the throttle, this is a natural reaction and will take some getting used to, teach your self to roll it off slowly in stead, this will be the first step to controlling your wheelie even if the wheel is only slightly lifted in a power wheelie.
Once you have the power wheelie sorted and you can control it, increase the revs to come up a little higher, do this to a height you feel comfortable with and practice for as long as needed.
Later on you may be able to reach the balance point, balance point is the point where you are no longer in a power wheelie where you have to increase the revs to sustain your height.
WARNING !!! there is a fine line between balance point and tipping over back wards at high speed. For low speed wheelies and stunting modifications are required.
At balance point you will find that slight throttle adjustments are required to maintain a steady wheelie, always have your foot over the back break lever as this is your "flip safe mechanism".