The main event on May 4 is the comemmoration ceremony on Dam Square, broadcast live on Dutch tv. Just before 8pm Queen Beatrix will place a wreath of flowers on the National Monument. At 8pm, 2 minutes of silence is observed (this is in the entire country), followed by a speech by mayor Job Cohen.
This is followed by a series of flower wreaths being laid by a variety of organizations.

On May 5 follows Liberation Day, on which the liberation from the Nazi occupation is celebrated.
One of the main events in Amsterdam is the Liberation Festival that takes place on Museumplein (the square behind the Rijksmuseum), from 12 noon to 11pm.
The other main event is the (outdoor) concert, that starts at 9pm, on a platform in the river Amstel, in front of the Carré Theatre. The concert is traditionally attended by the Queen and the Prime Minister. The concert has mainly classical music, and is very popular, so for a good place: be early!

See also the events page.