Volt Tackle is one of Pichu's, Pikachu's and Raichu's strongest attacks. It is learned by breeding a member of the Pikachu family with another one with a Light Ball.
Volt Tackle is an Electric type move, with 120 power and 100 accuracy. It is a Physical move.
Volt Tackle can cause paralysis, but also delivers to the user 1/3 of the damage inflicted. This move in power is equal to Thunder, but Volt Tackle has a 100 accuracy, where as Thunder has a 70 accuracy. The other difference between the two attacks is that Volt Tackle has recoil, where Thunder does not.
Pichu's, Pikachu's and Raichu's Volt Tackle is more powerful than Thunder, because they tend to increase more attack than Sp. Attack.
In Super Smash Bros. Brawl, Volt Tackle is Pikachu's Final Smash.
How to obtain
To get a Pichu that knows Volt Tackle, you must breed a female Pikachu that is holding the Light Ball with another Pokémon that is in its Egg Group. Your Pichu will hatch with Volt Tackle being known. Or, you can breed a Pichu with a Ditto and female Pikachu.
In Generation IV. Get a male Cherrim and a female Pikachu, put both in the day-care, and have Pikachu hold the Light Ball. Now, you should then have a Pichu that knows Volt Tackle.
Its Japanese name, Volteccer, is based on the signature move of the character Pulseman. Long before Game Freak made Pokémon, they created Pulseman, a Sega Genesis game. It should also be noted that Team Galactic and Rotom are also homages to Pulseman (Team Galactic based on Galaxy Gang, the main antagonists of Pulseman; and Rotom looks slightly like him—it can even go from the digital world to the "real world" and back in a similar fashion).