This information about the Dragonballs came from Saiya Generation.
The Dragonballs are powerful marble like balls
created by the Namekian elders. The Dragonballs
were originally created by Guru, the eldest Namek.
From there, other elders created Dragonballs to hide
them accross the plains of Namek. Dragonballs got
on to Earth with the arrival of Kame, an eldest Namek
of earth. He made 7 Dragonballs, but they were smaller
than usual the original ones.
The original Dragon, named Porunga, is located
on Namek. He has the ability to grant three wishes.
The dragon on Earth, named Shen Lon, has the ability
to grant one wish because of Kame's power. It is not
as great as Guru's. The wishes may be whatever as
long as it is in the creator's power. When the Dragon
is summoned, the sky turns pitch black and there is
a lot of radical lightning. The wind is like a hurricane,
and the oceans and lakes churn with power. The dragon
appears from the seven balls on the ground.
When wishing for your one or three wishes,
the wish is restricted to the power of the
Namek who created the Dragon Balls. For example,
when Vegeta and Nappa are heading toward Earth
for the first time, Master Roshi tries to wish
the two Saiyans away, but the dragon cannot grant
his wish. The wish exceeded Kame's own power.
Therefore, the wish cannot be too outrageous.
Unless you have the special ability to sense
power by thinking, you will have to find the
Dragonballs one way: with a device called a
The Dragonball Radar. The Dragonball Radar is
a radar which picks up on the imense power that
the Dragonballs possesses and homes in on that signal.