If you are talking about a TiVo, then no. The USB port is only for hooking it to a network. From there, you need to use Roxio Toast or TiVo Decode Manager.
If it's another DVR, then it might help to disclose which one.
or you could just get el gato/eyetv and it will work fine plus no monthly subscription fees plus has easy buttons for conversion for tv and iphone/ipod etc.