Governing bodies
International Tennis Federation: ITFtennis.com
ATP World Tour: ATPWorldTour.com
WTA: WTATennis.com
National Associations
Search for National Associations on the ITF website: ITFtennis.com
Events
Davis Cup by BNP Paribas: DavisCup.com
Fed Cup by BNP Paribas: FedCup.com
Olympic Games (tennis): ITFtennis.com/Olympics
Hyundai Hopman Cup: HopmanCup.com
Grand Slams
Australian Open: AustralianOpen.com
Roland Garros: RolandGarros.com
Wimbledon: Wimbledon.com
US Open: USOpen.org