Its all legal
This is a bit of a strange find.
I mean come on NES carts arnt exactly portable and this looks like it makes the DS thicker than a Game gear
I was unsure weather to put this here or in the retro bit
The Cyber Familator allows you to play original Famicom games on your DS Lite. It even has TV out for your convenience. There is no NES equivalent and there probably wont be any...ever.
The tv out connection sounds nice (but how do they do two player ?)