As Hilary mentioned earlier, gun salutes are planned at Green Park and the Tower of London later today to celebrate the new royal prince (details here) -- but that's not the only sonic celebration that will be going on in London.
At Westminster Abbey, where William and Kate were married in April 2011, the bells will be rung for three hours to mark the birth of a new heir to the British throne.
And at Buckingham Palace, there will be another musical nod to the new arrival, as CNN's royal correspondent reports: