The Opera software will release in June for roughly $32. Additional items of note include a May Japanese release date for New Super Mario Brothers (helloooo, import), a budget price for Tetris DS, the announcement of several games like Calligraphy Training DS and a cooking title, footage shown from Children of Mana and Xenosaga Episode 1-2, and "brief talk" concerning games such as Super Robot Wars, Dynasty Warriors, and Winning Eleven Nine (with the latter two titles getting Wi-Fi support).
More photos are available at the DS Advanced page linked via the image above (and the Read link below), as well as from the story on ITmedia and Watch Impress. A brief PR summary on Bloomberg has also been released, but a meaty DS Conference talk with slides (most likely from Satoru Iwata) has been provided on the Japanese Nintendo site here.
[Thanks, Tim, Ryan, Probot, Tim Tong, Justin, yamakiyo, and Badison]