Preparations for Michael Jackson's memorial service Tuesday are being made with Los Angeles city and county officials, who are anticipating a crowd of mourners that could top 750,000, according to sources involved in the planning.

2500 law enforcement officers are expected to be on hand to control the crowds, and fans are already pouring in to Los Angeles. The Los Angeles airport, hotels, and local and commuter rail hubs are already seeing a rise in Jackson-related arrivals, even as the Los Angeles World Airport and other public and private partnership members measure the holiday outflow, according to a partnership member.

Meanwhile, social media monitors for officials report that "Michael Jackson memorial attendance"-related Tweets on Twitter are now the most talked about topic and are accounting for 23 percent of all tweets, topping 6000 per min.