From the game freak guy in between Pastoria and Veilstone.
See all Pokemon and beat the league then go to proffecer oak in proffecer rowans lab.
"Your next destination is Hearthome City, which is due south of Eterna City via the Cycling Road. On the way out of town youll run into on of Prof. Rowans assistants, who will check your progerss and reward your continued efforts with the Exp. Share item (if you've seen 35 or more pokemon)." - Page 65 of Pokemon Pearl/Diamond Guide. So, go to Eterna City, and go down and through the Building at the bottom of the city (leads to Route 206), and if Prof. Rowans Assistant doesnt give you it, then im not sure. Im just showing what the guide says.
In Pokemon Diamond, you can get the exp. share from Rowans Aide.
YesFireRed & LeafGreen- Sliph Co. Floor 2 Ruby & Sapphire- your house next to ur momDiamond & Pearl- Rowans LabThat's what i know
The Rowans - album - was created in 1975-05.
you cant get a diamond on Pokemon pearl but you can get a pearl on diammond ...and pearl.
Rowans lab after you have filled up normal pokedex, prof oak will give it to you to you but if you use the AR like me when u get 151 Pokemon and u go and try to talk to rowan he just sais go on and enjoy your edventure or sumtin like that....
he gives it to you in prof. rowans lab. for this you have to complete sinnoh pokedex(excluding event pokemon).
all you have to do is see every Pokemon in the sinoh dex then you go to prof rowans lab and he will give you your national dex
you find him in eternea city near the bike road in a small house.
Yes, you can get it on Pokemon Pearl.