"Muslim tradition requires burial within 24 hours, but by doing it at sea, American authorities presumably were trying to avoid creating a shrine for his followers." [http://www.nytimes.com/2011/05/02/world/asia/osama-bin-laden...]
"It was 3:50 on Sunday afternoon when President Obama received the news that Bin Laden had tentatively been identified, most likely after a series of DNA tests." [http://www.nytimes.com/2011/05/02/world/asia/02reconstruct-c...]
Another article said that the burial at sea was completed by 2 AM EDT (so they presumably were done by 3 PM in Pakistan, about 14 hours after the first tweet).
Today's news are more accurate on that matter: "At 2:05 p.m., Mr. Panetta sketched out the operation to the group for a final time. Within an hour, the C.I.A. director began his narration, via video from Langley. “They’ve crossed into Pakistan,” he said." [http://www.nytimes.com/2011/05/03/world/asia/03intel.html?pa...]
This is exactly what the Israelis did with Eichmann.