Here you will find some info on the Dragonballs
Earth Dragonballs
1 The person/people must gather all seven DragonBalls.
2 A chant is required (Such as "Come out, Shenlong, and grant my wish!").
3 Only one wish per summoning of Shenlong.
4 After the wish is made, Shenlong will disappear and the DragonBalls will turn to stone and scatter themselves; they will remain stone for one year.
5 The Shenlon cannot grant any wishes that are beyond the powers of the creator of the DragonBalls.
6 You can revive anyone or any group of people who fit a certain requirements, if they did not die of natural causes.
7 If a person has been revived by Shenlong before, the person cannot be revived again.
Namek Dragonballs
1 The person/people must gather all seven DragonBalls.
2 A chant is required in the Namek language.
3 Wishes must be said in the Namek language.
4 There are 3 wishes per summoning of Puronga unlike the one of the Earth balls.
5 After the 3 wishes are made, Puronga will disappear and the DragonBalls will turn to stone and scatter themselves; they will remain stone for 130 days.
6 Puronga cannot grant any wishes that are beyond the powers of the creator of the DragonBalls.
7 You can revive anyone multiple times, as long as he/she did not die of natural causes.
8 You can only revive one person per wish.