Thanks to RingbearerNZ for this awesome compendium of all of the Heroes news that we have so far!

SEASON 3 GENERAL DETAILS
Heroes Season 3 will have 25 episodes.

Volume 3 Villains will have 13 episodes, which will be released in one go.
Season 3 will return to the model of Season 1. The only difference is that Season 3 will start with much faster pace.

SEASON 3 EPISODE TITLES
Episode 3×01: “The Butterfly Effect”
Sept. 15, 2008
Written By: Tim Kring
Directed By: Allan Arkush

Episode 3×02: “Dreamtime”
Sept. 2008
Written By: Tim Kring
Directed By: Greg Beeman

Episode 3×03: “One of Us, One of Them”
Sept. 2008
Written By: Joe Pokaski
Directed By: Sergio Mimica-Gezzan

Episode 3×04: “The Year of Our Lord”
Fall 2008
Written By: Aron Coleite
Directed By: Adam Kane

SEASON 3 SPOILERS
Sendhil Ramamurthy (Mohinder Suresh) is thrilled by what awaits his character this season.
Angela’s power will be revealed and her role will be very important (we already knew that…)
Our Heroes will have to save the world at least in two occasions this season.

We should learn more about evolution of powers.
Expect huge surprises and a new series regular
We will learn more about Angela and Kaito and their group
Show will play with time and space and “where people are on the planet”
Villians will be a key and not necessarily people we have met before, but it will be clear who they are
Expect a lot of Sylar
Expect Angela Patrelli to make some “grey area” decisions
Parkman will be “flashing someplace” and it will be one of the surprises
Major storyline will be the origins of the powers and the “genetic essence of the power”
When asked about Future Hiro returning, Arkush confirmed that there are “multiples” of the same people
Confirms that the chaos theory is one of things the season is about and references the Butterfly Effect from saving the World.