This year will be Anime Expo's 20th anniversary!
It will be held from July 1-4 at the Los Angeles Convention Center, you can visit the site here for more information- http://www.anime-expo.org/

Here's what has been announced so far:
-Over $25,000 in cash and prizes for the Masquerade
-Over $10,000 in cash and prizes will be awarded to category winners in the AMV contest
-The world premiere of "LASTEXILE -Fam, The Silver Wing-"
-Anime Expo Dedicates Annual Charity Auction To Japanese Disaster Relief
Guests of Honor:
-Danny Choo
-Fred Gallagher
-Hatsune Miku
-Hirano Katsuyuki
-Itoh Hiroyuki
-Izumi Matsumoto
-Kalafina
-Miyuki Sawashiro
-Onyx Kobayashi
-Sohei Niikawa
-Kenta Sugano
-Maon Kurosaki
-Vic Mignogna
-Wataru Sasaki
-Nirgilis
-Seiji Mizushima
-Taliesin Jaffe
-Toshiyuki Morikawa
-Koichi Chigira
-Makoto Kobayashi
-Takaaki Suzuki
-Hiroyuki Birukawa
-Toshio Furukawa
-Madhouse Studio Creators: Tetsuro Araki, Masayoshi Tanaka, and Kentaro Hashimoto
Industry Guests
-DANCEROID
-Power Rangers
-President of Good Smile Company, Takanori Aki
-Toshihiro Fukuoka
-President and Chief Producer of Nitroplus, Takaki Digitarou Kosaka

I will edit this and add to it when more announcements are made.