So Derek Neal, producer for Street Fighter III Third Strike: Online Edition, has revealed some of the upcoming DLC for the game. On September 6 or 7, you can expect to see "Color Pack 1", which will offer seven new colors for each character i the game. The colors are available in nearly all the modes, but if you're playing against someone without the DLC, they won't see the pretty new colors. (They also won't save in replay files, so FYI.) It's up to you to decide whether or not new color palletes are worth $2.99.
Then, in the next month or so, there will be more DLC, like music packs that add character themes from the first two Street Fighter III games. Then there will be Match Packs, which will contain over an hour of content from the Fight For the Future 2011 tournament held at the Capcom offices this year where 16 expert SF3 players from around the world kicked each others' asses. The first Match Pack will cover the entire top eight of the tournament, and the second will be a "best of" compilation of the matches. No date or price on those, yet, though!