If anyone doesn't watch D.Gray-Man but reading its Manga you can count on me. I will give you some links where you can watch D.Gray-Man Japanese dub(English-sub). Unlike youtube this links are full episodes estimating 22 mins. There are also English-dub BUT its only upto 53 episodes.
Now I will give you the Links:
http://www.animefreak.tv/watch/dgray-man-english-dubbed-online-free (japanese-dub(english-sub)) works on any web browsers
http://www.kumby.com/category/d-gray-man-episodes (japanese-dub(english-sub)) works on firefox only
http://www.watchcartoononline.com/d-gray-man-episode-1-english-dubbed (english-dub) works on any web browsers upto episode 53 only
If these links are helpful or not don't hesitate to comment it'll be okay to me!