TiVo AG0100 Wireless G USB Network Adapter for TiVo Series 2 and Series 3 DVRs
My TiVo Wireless Adapter review
It was easy to hook up and it works great.  With the adapter I can get the latest weather and traffic information for my area, as well as play games and listen to podcasts.  I'm very happy with this purchase, in fact, I just bought another one yesterday.