I haven't tried it myself yet, only because I HATE taking pills, but have heard a few success stories about Glucosamine and Chondroitin. Another thing you can do is start physical therapy. Strengthening the muscles and tendons around the joints helps to slow the degenerative changes.
First, go to an orthopedic doc, not your general practice doc. Get xrays, especially a standing xray if it's in your knees or ankles. My doc started me on Relafen (sp?) and physical therapy- The pills take the edge off the pain and the therapy will (hopefully) help strenghten the muscles around my joints. Good luck!