Bavarian Technic might be the easiest out-of-the-box solution, but not the cheapest.
http://www.bavariantechnic.com/
A cheaper INPA K+DCAN cable will work, but it's a hassle finding the software since it is technically not for public consumption and any copy you find has been leaked, so there's dozens of configurations floating around. That said, the One-Stop cable is the de facto forum standard for K+DCAN:
http://www.one-stop-electronics.com/...&product_id=16