Phillips said all of the details would be finalized when he meets with the Jackson family Thursday afternoon.
"Everything is in preliminary stages except the place and time," Phillips told NBC.
AEG Live is the organization which was behind Jackson's planned 50-show stint in London.
Should capacity be reached for the nearly 20,000-seat stadium, Phillips said the overflow crowd will be able to watch the memorial on large screens at nearby Nokia Plaza.
Despite reports that the public ceremony will be a funeral, a source close to the situation previously told Access Hollywood executive producer Rob Silverstein it will actually be a memorial to the King of Pop, who died last week at the age of 50.
Related Content from AccessHollywood.com:
VIEW THE PHOTOS: Michael Jackson: The Life Of An Icon
PLAY IT NOW: Jermaine Jackson Talks Michael Jackson's Passing On 'Today' (July 2, 2009)
PLAY IT NOW: Michael Jackson's Will Revealed (July 1, 2009)