Hormone refractory prostate cancer refers to advanced disease in which the patient no longer responds to conventional hormonal treatment. When hormone therapy is no longer successful, chemotherapy is a treatment option. However, current single-agent treatment has shown to have limited benefit. In this clinical trail, investigators are evaluating the effectiveness of Zoledronate(Zometa) combined with Estramustine and Docetaxel (Taxotere) in the treatment of patients with hormone refractory prostate cancer. Zometa is a bisphosphonate, and may reduce or delay skeletal complications caused by bone metastases. Estramustine and Taxotere are chemotherapy drugs that have shown activity in hormone refractory prostate cancer. Eligible patients will be randomized to receive Estramustine and Docetaxel (Taxotere) in combination with Zometa or Zometa given alone.