On twitter I follow #CNNBreaking and BBC's equivalent. Its the only place you wont hear sensationalized news give or take a few places.
The UK pays plenty of cash to charities and humanitarian efforts. Billions a year. The 20 million is the cost of security etc. associated with the event. It sounds like a lot, but it is comparable to many large public events involving such people. The royal family are paying for the actual wedding itself. Supposedly, tourism revenue generated from the event will more than pay for the costs incurred to the tax payer. I'm not a royalist, but the people whining about the cost should see the Libiya tax bill if they want to get excited about something.