My grandsons came to live with me in June 2005 due to Child Protective Services removing them from the mother's home. I was awarded custody of them in August 2006. Then in September 2009 we went to court and the father was awarded custody of the boys with the mother getting 8 supervised visits through a court program. She NEVER signed up for the program nor has she made any attempt to see the children since. We (the father, step mother & I) are wondering if we can petition the court to have her parental rights revoked so the step mother can adopt them? What steps do we need to take?

Certainly you can go back to Court and get her rights revoked and get her held in contempt. Forcing her to surrender her children for adoption is not that easy and the Courts are reluctant to do so.

The only person who is a party to this is your son, the father. He has to file the documents.

... We (the father, step mother & I) are wondering if we can petition the court to have her parental rights revoked so the step mother can adopt them? What steps do we need to take?
You, a grandparent, wouldn't join in your son's and daughter-in-law's petition for step-parent adoption.

The findings the court needs to make, regarding whether the court may dispense with the mother's consent to a step-mom adoption, will vary from state to state. Assuming you are in the U.S. what state is it?

First step, of course, is to consult with an attorney in your jurisdiction.