When Is My Child Emancipated

My Ex and I both live in Colorado, but at either end of the state. My son lives with his father most of the year. He is eighteen and will be a senior in high school this year. He graduates in 2011. He has a full time job that keeps him at home and I don't get to see him as often as the court has ordered. His father is now saying that he won't drive him to the court ordered location that was agreed upon as our son is now 18(but is not licensed and does not own a vehicle.)

I am unemployed and I have two children(ages 3 and 1)from my current marriage. I am a stay at home mom with several physical ailments that keep me from working a job(I have yet to file for disability.) I owe close to three thousand dollars in arrears, and pay $281.00 a month in support($256.oo in monthly installments and then $25.oo for arrears.) My husband actually pays it because it is court ordered and I don't want to have my driver's license suspended or be put in jail for non-payment.

I was just informed that although my son will be 19 in early October, I may very well have to pay support until he is out of high school. Is this true? How do I go about finding how emancipation works? What the definition for it is? He is not handicapped and does not need state aid.

Thanks for your help!