This movie is based on the true story of one of the most intriguing unsolved crimes in the nation's history. 

"Zodiac" is a thriller from David Fincher, director of "Se7en" and "Fight Club."

A serial killer terrifies the San Francisco Bay Area and taunts police with his ciphers and letters.  Investigators in four jurisdictions search for the murderer. The case will become an obsession for four men as their lives and careers are built and destroyed by the endless trail of clues.

Also starring Jake Gyllenhaal, Mark Rufalo, Robert Downey Jr., and Anthony Edwards.

This thriller is due for release in March, 2007 in the U.S.

Here are some Zodiac links for more information:
 

Official website.

Trailer for Zodiac.

Horror channel.

San Francisco Chronicle article.