The standard wifi battling rules!

The Standard Battle Clauses/Battle Rules:

Evasion Clause
Moves that boost evasion (i.e. Double Team and Minimize) are not allowed.

Freeze Clause
Two or more Pokémon on a team cannot be frozen at the same time.

Sleep Clause
Two or more Pokémon on a team cannot be asleep at the same time. Self-induce sleep via rest does not activate Sleep Clause.

OHKO Clause
One-Hit KO moves are not allowed.

Species Clause
Two or more of the same Pokémon may not be used on the same team.

Self KO Clause
If both players have only one Pokémon left, moves which KO both the user and the opponent are not allowed (e.g. Explosion, Destiny Bond). If recoil damage would cause a tie, Self KO Clause does not activate, and the player who last attacked is the winner. (These rules only apply for Tournaments here, or if your opponet chooses this clause to be in affect)

Item Clause
All Pokémon on a team must hold different items. This is not a standard clause in competitive play, but it is used in Nintendo tournaments. (We might have this in affect in some Tournaments here)

Source: From smogon.com