The viral marketing campaign for The Dark Knightis back in full swing, and this time around it seems to be focused on Aaron Eckhart's Harvey Dent. By heading over to IBelieveInHarveyDent.com, fans can sign up to "Join the Fight for Gotham".

CLICK HERE if you want to sign up to help Gotham City's District Attorney clean the city up.

If you do register with the site, you'll get a confirmation e-mail that says:

Citizens of Gotham! The future of our city rests in your hands!

Alone, we are helpless against the thugs and killers menacing our city.

Together, we have the power to take back Gotham.

In just a few days, you'll find out how.

Check back with MovieWeb and SuperheroFlix for more details about how you can help Gotham City. We'll keep you informed as soon as "a few days" have passed.

At this point, the other viral marketing sites such as WhySoSerious.com and The Gotham Times have not been updated.

The Dark Knight opens on July 18, 2008, and stars Christian Bale, Heath Ledger, Morgan Freeman, Gary Oldman, Aaron Eckhart and Maggie Gylenhall.