A couple weeks back, Nintendo announced it would release a headset for the Nintendo DS in Japan come September 14. GoNintendo has unearthed Japanese web store HMV's product page for the accessory, complete with stylishly arranged yet blurry product photo.
Nintendo of America has announced no plans to release the headset stateside. Such an accessory would go well with several games making use of mic functionality, such as Nintendogs or Metroid Prime Hunters.