NYT: Al Gore to Endorse Obama Monday, 16 June

Yes he will--and about time too. From campaign email:

A few hours from now I will step on stage in Detroit, Michigan to announce my support for Senator Barack Obama. From now through Election Day, I intend to do whatever I can to make sure he is elected President of the United States.

Over the next four years, we are going to face many difficult challenges -- including bringing our troops home from Iraq, fixing our economy, and solving the climate crisis. Barack Obama is clearly the candidate best able to solve these problems and bring change to America.