If you go to the end of Route 11 (past all those trainers) there is a building. It has a set of stairs in it ... talk to Professor Oak's aid and you can get the Item Finder. Of course you have to have caught at least 30 Pokemon before he'll give it to you ... good luck ^.^
you cant. you have to use the itemfinder
when you have got the itemfinder. Click start then click on bag and then press the right button on your +control pad. click on the itemfinder then click use. The itemfinder will detect any items around you that are berried.
. underground path in Celedon city
Press "A" on the right spot xD
Use the itemfinder where Mr. Fuji was in the Pokemon Tower.
You should be able to receive an Itemfinder off one of Professor Oak's aides on Route 11. However, you need to have captured 30 Pokemon or more to receive it.
Go east of vermillion city until you find a big building go in go upstairs and talk to the oak aide he will give you the itemfinder.
Rocket Hideout in Celadon Game Corner. Use itemfinder near where Giovanni was.
Find the oak aide that gives you the itemfinder which should be in the big building east of vermilion city he will ask if you have recorded 30 Pokemon in your pokedex if you did say Yes he will give you the itemfinder.
Go to professor oak, Talk to him, he will give you the "super itemfinder" use it when using the map
First record 30 Pokemon or more in your pokedex once you complete that head to vermilion city then go east go inside the big building and go upstairs talk to the scientist and say YES to his question you will get the itemfinder.
The itemfinder works when it finds a secret item around your current area for example on One island if you go south you can reach a treasure beach using the itemfinder you can spot hidden items and dig them up. Also if you use it where snorlax and Giovanni and mr fuji used to be you will find super secret items.