I have a felony on theft. It happened on 2006 I was 18 that time. Now I am interested in joining the military?

which military would accept me? I just recently graduated on May 12, 2011 with a bachelor of science, I've always been interested in joining but my parents never let me. Now that I am going for it. Please be serious this is a serious situation. I know it was a big mistakes in my life now I am 25. thanks guys