The drug that will be used in this study is called Azacitidine. Azacitidine belongs to a group of drugs which may restore normal control in cancer cells by affecting the genes and proteins in the body. Azacitidine is approved by the FDA for the treatment of Myelodysplastic Syndrome (MDS), a pre-leukemic bone marrow disease. The purpose of this study is to find out what effect the drug Azacitidine has on Acute Myeloid Leukemia (AML) in elderly patients.