Steven Irwin memorial at Australia Zoo Wednesday

BEERWAH, Australia -- More than 5,000 people, including the Australian prime minister, are expected to cram the "Crocoseum" at the Australia Zoo Wednesday to say farewell to "Crocodile Hunter" Steve Irwin at a memorial service.\nFlags on the Sydney Harbor Bridge were to fly at half-staff, and giant television screens were set up in Irwin's home state of Queensland for people to watch the service.\nIrwin, 44, was killed Sept. 4 when the barb from a stingray pierced his chest while he was filming a TV show about the Great Barrier Reef. His family held a private funeral service Sept. 9.\nHis death set off an outpouring of grief. Tens of thousands of people traveled to the zoo near Brisbane to drop off flowers and other mementoes, many of them signing Irwin-styled khaki shirts instead of a condolence book.\nThere has been a surge of donations to the Irwin-instituted charity Wildlife Warriors, and millions of people have visited his Web site to find out more about Irwin and his conservation efforts.\nIrwin's widow, American-born Terri Irwin, is expected to make her first public appearance since his death at today's memorial service. The couple's daughter, Bindi, 8, and son Bob, 2, are expected to accompany their mother.\nPrime Minister John Howard also is expected to attend the service, and country singer John Williamson plans to sing "True Blue," a song Irwin loved.\nJohn Stainton, Irwin's manager and close friend, said the service will be a celebration of the naturalist's life.\n"There will be one seat alongside of the family for Steve because he loved the Crocoseum -- he built it," Stainton said. "And his Australia Zoo cap that he always wore watching all the shows with his daughter will be on the seat."\nStainton said there will be visual tributes to Irwin, with some "memorable film clips" and "funny moments" from his television career. Actor Russell Crowe reportedly will be among those paying tribute by video.\n"The one thing I hope everyone will take away from it is what a diverse character he was," Stainton said.\nThree of Australia's main television networks plan to carry the ceremony live and provide feeds to U.S. and international networks. The service is expected to start at 7 p.m. EDT.