N3dES- 3DS Mode NES Emulator
Today CollosalPokemon released the first 3DS Mode NES emulator for the Nintendo 3DS. This emulator which runs from the 3DS Browser can play homebrew NES ROMs without a flashcart or an exploit, granted VERY slowly because of Nintendo put restrictions on processing power in the 3DS Web Browser's canvas/javascript abilities.
While the 3DS is not yet hacked that doesn't mean there can't be homebrew emulation running through the 3DS Browser, which runs in 3DS mode. Again, granted the emulation is VERY slow because of Nintendo putting limits on the processing of many elements but it is custom NES emulation running in 3DS mode 3DS Web Browser.
Go to this page on your 3DS : n3des.byethost6.com
Note: This is a 3DS-only page so you'll only be able to browse this on your 3DS
Pros:
* No flashcart needed
* Region Free NES emulation
* Virtually no graphic bugs
* Runs NES homebrew ROMs
* Runs in 3DS fullscreen as much as possible (there are still the 3DS web browser's 2 HUDs)
* Uses touchable buttons not physical buttons (not all button codes for 3DS are known but as I've tested retrieving a physical button click on the 3DS is really slow so touch buttons are faster)
* Can pause gameplay at any time anywhere in the game
* Can reset/reload game
* Can be used on a retail 3DS unit.
* Can emulate NES Zapper through touch screen (note: input is slow due to javascript limitations)
Cons:
* Can not save to your SD (although not many nes games can/actually need to save)
* VERY slow (< 1 FPS) (Again, this is a proof-of-concept release)
* Can not use ROMs from SD
* Requires an internet connection
* No sound (currently not known how to play custom sounds on 3DS through javascript in the browser)
* Restricted to 65KB ROM or less (working on support for bigger ROMs)
Source- gbatemp
