It's now official Super Street Fighter IV Arcade Edition will be released this summer as a DLC. The latter will contain a new balancing as well as four new characters: Yun and Yang, Oni and Evil Ryu. Screens inside then gameplay videos.
Update: Videos now online.

Capcom has announced that a costume DLC for Super Street Fighter IV will be released on October 26th on both XBL and PSN. No info on pricing, but here are a trailer and some images of it. Please not that it will also be available for PC, but later.

Capcom has released these 3 new trailers of Super Street Fighter IV at the same time. Fans should appreciate.
Update : Images from the first free DLC added

Capcom has revealed the last character that joins the new cast of Super Street Fighter IV. Hakan, an original oil wreslter, watch his skills with the trailer and a gallery inside. The game is still expected for a late April release.
Update: Gameplay video added.

Super Street Fighter IV will ship at the end of April and Capcom released a few new screenshots presenting Gouken and Gouki. Warm up your sticks, the game will be available in late April.

Capcom just confirmed that Makoto, Ibuki et Dudley, all escaped from Street Fighter III 3rd Strike, will be playable in Super Street Fighter IV. Images, trailer and videos inside!

Capcom is back already with this new ultra stylized trailer of Super Street Fighter IV.

Capcom released these images of Super Street Fighter IV and also revealed the game will be available on April 27 in North America and April 30 in Europe. Since we are talking about Capcom, they also announced that Lost Planet 2 will have a worldwide release on May 18 and that the 360 version will feature two guest stars, as Marcus and Dom from Gears of War will be downloadable as bonus characters.
Update: Super Street Fighter IV trailer added.

Capcom also released these new images of Super Street Fighter IV, along with a brand new trailer and two fights videos.

It's been first announced in Famitsu a few days ago, but here are the official images and trailer of Super Street Fighter IV showing Guy and Cody from Final Fight and Adon from Street Fighter Alpha in action.