You find him at the silver rock, but only if you have oak's letter, which hasn't been released by nintedo yet I'm pretty sure. But if you have a AR code he will be there, good luck.
a video to help :)
http://www.YouTube.com/watch?v=88MBGbolBZU
in Route 224
The event scene in Pokemon Pearl where the player meets Professor Oak on route 224 is part of a Nintendo-sponsored special event in order to obtain the legendary Pokemon, Shaymin. The player must be involved in the special event to obtain the key item called Oak's Letter, and afterwards Professor Oak will appear on route 224.
Professor Oak will not appear directly in the Flower Paradise, he'll appear at the start of the long route by it called Seabreak Path which is by the white rock in Route 224 however he'll only appear there if you have the key item Oak's Letter.
You have to go to the Victory Road then to Route 224 and then at the top of the route you will see a white rock, there is standing Proffesor Oak talk to him and then you will see what happens I hope this helped u
Professor Oak cannot be seen on Route 2.
in Route 224
In the wild or from professor oak
You can't access Route 224 until professor Oak upgrades your Pokemon. Then go east of Victory Road. Route 224 is the eastmost Route in Diamond Pearl and Platinum.
The event scene in Pokemon Pearl where the player meets Professor Oak on route 224 is part of a Nintendo-sponsored special event in order to obtain the legendary Pokemon, Shaymin. The player must be involved in the special event to obtain the key item called Oak's Letter, and afterwards Professor Oak will appear on route 224.
route 224
He goes to Route 224...
Professor Oak will not appear directly in the Flower Paradise, he'll appear at the start of the long route by it called Seabreak Path which is by the white rock in Route 224 however he'll only appear there if you have the key item Oak's Letter.
You have to go to the Victory Road then to Route 224 and then at the top of the route you will see a white rock, there is standing Proffesor Oak talk to him and then you will see what happens I hope this helped u
After you gain Oak's letter you can go to route 224 and catch shaymin
route 224 is where you get shaymin.but, you can not get shaymin until you get oak's letter by wireless connection,from a friend, or by action replay code, oak's letter.
yoy have to get oaks letter, then go to route 224 and go to the big rock and proffessor oak should be there yoy have to get oaks letter, then go to route 224 and go to the big rock and proffessor oak should be there yoy have to get oaks letter, then go to route 224 and go to the big rock and proffessor oak should be there yoy have to get oaks letter, then go to route 224 and go to the big rock and proffessor oak should be there
visit pal park in route 221 and he will be there. After that u can find him in his house.