First, for your cars, you could use our KEY series interfaces which sell for $250.
An SKC# is needed to program keys and so on for the immobilizer in the car. The SKC is the equivalent of your bank account's PIN number. It is a unique number that is used to identify the user who is going to change the key coding. Without the SKC, you cannot gain access to the information needed to change the settings.
Having said all that, since you have a '01 vehicles, it may be that you don't need an SKC as the vehicles may not have the immobilizer. :-)
If you do not have an immobilizer, and I think that you probably do not, then you would use this procedure to match the key remote: