The interplay in prostate cancer bone metastases between the 'seed' (the prostate cancer cells) and the 'soil' (the bone microenvironment) has been increasingly recognized as integral to the remarkable tropism for bone shown by prostate cancer. Increasing research into this area is elucidating the mechanisms involved in this complex 'cross-talk'. Recent developments, including the use of bisphosphonates in metastatic disease, highlight the important role of bone cells in the development and progression of metastatic prostate cancer. We review the current reports emphasising these possible mechanisms and indicating possible factors for future treatment directions.