Hi, I am an Australian and have a child with a US citizen. We were married for eight years and are now divorced. We divorced on good terms without lawyers etc and are still friends and neither of us has new partners. She says that she wants to take our son back to the US to live and would like it if I could also go there to live so I can be a part of his life. Is it possible for me to also go to the US to support my son? He is three years old.

Go to the US Immigration website. I think you need to be able to show that your occupation skills are needed, unless she can sponsor you.

Your status is divorce, so you may have to get US visa in categories other than family/spouse.