From BBC Sports:

F1 2006 schedule:

Mar 12: Bahrain Grand Prix (Bahrain)
Mar 19: Malaysian Grand Prix (Sepang)
Apr 2: Australian Grand Prix (Melbourne)
Apr 23: San Marino Grand Prix (Imola)
May 7: European Grand Prix (Nurburgring, Germany)
May 14: Spanish Grand Prix (Barcelona)
May 28: Monaco Grand Prix (Monte Carlo)
Jun 11: British Grand Prix (Silverstone)
Jun 25: Canadian Grand Prix (Montreal)
Jul 2: United States Grand Prix (Indianapolis)
Jul 16: French Grand Prix (Magny-Cours)
Jul 30: German Grand Prix (Hockenheim)
Aug 6: Hungarian Grand Prix (Hungaroring)
Aug 27: Turkish Grand Prix (Istanbul)
Sep 10: Italian Grand Prix (Monza)
Sep 17: Belgian Grand Prix (Spa-Francorchamps)
Oct 1: Japanese Grand Prix (Suzuka)
Oct 8: Chinese Grand Prix (Shanghai)
Oct 22: Brazilian Grand Prix (Interlagos)

Some switching around next year.