When the 3DS was first announced by Nintendo of Japan, It was stated that the release will be by the end of the fiscal year, which ends March 31st 2011. Reggie himself has now gone on record to confirm this for more then just Japan.

“The one thing, for sure, is that we will launch in all of our major markets by March 31, 2011.”

Reggie goes on to say that the 3DS design shown off at E3 is not the final design. My best guess, we will be seeing the 3DS in March here in the states.