Sescom makes a wide range of DSLR adapter cables.
http://www.sescom.com/productlist.asp?cat=DSLR-Audio-Cables
All you would need is a TA3 - 3.5mm adapter cable.
http://www.sescom.com/productlist.asp?cat=DSLR-Audio-Cables
All you would need is a TA3 - 3.5mm adapter cable.