At 12:48 PM 5/15/97 -0700, you wrote:

   Are there two sets of Dragon balls?  If  not, why did they scatter all
over  the universe instead of all over the  earth in DragonBall GT?  I am
writing  a Ranma/DB cross over and this is a  fairly important point for my
plot development.  Thank ya  much!  

There are several sets.

First, we have the upgraded earth set, which allow 2 wishes at once, or one
wish, and another six months later.  They scatter to the four corners of
the earth after use.

Second, we have the Namek set, which allow 3 wishes, or one wish or more
now, and the other one or two later.  Namek has a shorter year, so the
others can be made, and the balls become active again in a shorter time.
They go nowhere after use.  (convienient, ne?  ^_^)

Third, we have the Galaxy (?) Dragon balls that got used at the beginning
of GT.  I'm not too sure about these, but they only grant one wish, and
scatter all over the cosmos after use.

Please avioid GT, also known as 'Let's mess up the character designs and
get even more ridiculously powerful than normal'

Good luck on the fic...we need more good DBZ fanfic out there...  ^_^