Sean Penn and Matt Damon on Castro Street

The long will-it-or-won't-it-be-made story of the film adaptation of Randy Shilts' book The Mayor of Castro Street has taken another turn.

With news of Gus Van Sant's attempt to shepherd the project to fruition comes fresh casting news: Sean Penn is attached to play San Francisco's pioneering gay activist/public official, the late Harvey Milk, and longtime Van Sant collaborator Matt Damon is in talks to star as Milk's assassin, Dan White.

Over the course of this project's lengthy coulda-been/shoulda-been life, a number of actors have simply aged out of the title role, Robin Williams included.

Hopefully, Van Sant will have the wherewithal to make cameras roll sooner rather than later, or else Zac Efron will eventually be old enough to take the lead.

If all goes as planned, look for Mayor sometime in 2009.