There are Pokemon Centers in every town/city.
There isn't a Space Center in Pokemon Diamond and Pearl.
in the center of sinnoh
Solaceon town.
it is in solaceon town
next to the Pokemon center
in canalave city under the Pokemon center
You can get 2 eevees in Pokemon pearl by breeding the eevee you get from Bebe ( her house is next door to the Pokemon center in Hearthome city) with a ditto in the daycare center in Solaceon town.
With the happiness checker you get in the Pokemon center in etera city.
you can't you have to go to the Pokemon center and go to bebe's PC
It depends on which town but if you have a pokemon that knows fly, you will be flown right in front of the pokemon center.
either 1 or 2 to the left of the Pokemon center
In jubilife city . West of the Pokemon center.