No, Rayman 3D on the Nintendo 3DS isn’t a port or remake of the original Rayman. Nor is it the 3DS version of Rayman Origins that Ubisoft once hinted at. It’s actually a 3D adaptation of Rayman 2: The Great Escape on the Dreamcast.
Ubisoft say they’ve made tweaks to the game with regard to accessibility, progression and the learning curve. Rayman 3D doesn’t have a release date, but it is one of the Ubisoft titles in the 3DS launch window, between March and June 2011.