Opera for the DS is forthcoming, and also revealed an upcoming TV tuner attachment for pulling in over-the-air broadcasts. Very few details are known about either product at this point, although Nintendo has said that the browser will start shipping in June for around $32. Neither a price nor a release date have been mentioned for the tuner. Follow the "Read" link for more pics...
Update: More info at Joystiq, here.
Update 2: Just to clarify, the TV tuner is only capable of receiving "One-Seg" broadcasts. "One-Seg" is a kind of terrestrial digital broadcast, meaning this TV tuner cannot receive traditional analog TV broadcasts. Unless more countries hop on the One-Seg boat in the near future (Japan is set to launch One-Seg broadcasts on April 1st of this year), it's extremely unlikely this accessory will ever get outside of Japan.