Dgc1808 on 02 October 2008
Diamond -
Dialga
Mime Jr.
Skunky
Skunktank
Cranidos
Evolved Cranidos
Pearl -
Palkia
Bonsly
Glameo
Purgley
[Triceratops pokemon, forgot the name]
[evolved form of triceratops pokemon...]
Those are the only differences Pokemon wise that I can remember. The story is the same on both. Gameplay is also the same. I think on pearl the menu's may look a bit more colorful and pink. Not sure about that though. Ask someone else.
If you pick either tape you'll get the same experiences, and there is trading over wifi globally, so you don't really have to worry about getting the other pokemon from the other tape.
Sorry If I spelt any of the pokemon's names wrong...
EDITED.
4 ≈ One
