I recently replayed Monkey Island 2, this time using SCUMMVM for the DS. But Sam & Max: Hit The Road doesn't work on the DS with voices, at least last time I checked.
There's probably a Wikipedia article on SCUMMVM. I think SCUMM stands for something like "SCript Utility for Maniac Mansion", and VM is "Virtual Machine". It's a way (an emulator, I guess) of running SCUMM-based games (many LucasArts games, but also other point-and-click adventure games like Simon The Sorceror) on many, many other platforms, including the DS. It's amazing how well it works.