Go back to a time when "DX" was used to append ports instead of "3D" or "DS."
Nintendo had two demos of the 3DS Virtual Console on display at their event in New York City. One of them was The Legend of Zelda: Link's Awakening DX. The title is the 1998 Game Boy Color re-release of Link's Awakening, which initially came out in 1993 on the Game Boy.
Link's Awakening looks great on the top screen of the 3DS, and it especially benefits from actually being in color unlike its Virtual Console counterpart Super Mario Land. It's exciting to know that this gem of a Game Boy title will be out right away when 3DS Virtual Console hits.
The controls for the game show up on the bottom screen. This might have been just for this demo, but I personally hope that feature stays in the final release. It's nice to be able to see what each button does on the fly, though I hope they use the bottom screen in more interesting ways, such as displaying your online friends list or letting you access the game's manual while playing.
There is no set release for the 3DS Virtual Console. However, Link's Awakening is slated to be a launch title for the service when it hits. No pricing has been announced.