Sorry to say, but Wii Sports isn't compatible with online play. Only certain games can go online and let you play with other people. What games that can connect to wi-fi will always have this blue-white logo on the upper-left hand corner of the game's cover, as seen here.
Just for the sake of noting this, a small amount of games will have a red logo instead of a blue one, saying pay to play, as seen here.
If it has that logo, it will be able to go online and play with others, but you'll have to pay a fee in order to play. You could say it's like buying minutes for a cell phone. Hope this helps.