mitsu

Best answer as chosen by Asker / Ratings
Get a Pokemon that has the ability 'pickup'. In emerald, you can find most of these pokemon. But not all.

The Pokemon that have the pickup ability are: meowth, phanpy, zigzagoon, linoone, aipom, ambipom, pachirisu, munchlax and teddiursa.

In emerald, the level of the items and frequency at which they will find these items will depend on the pokemon's level. Make sure it is not holding an object.

If you want to see exact levels and items, go to:

Http://www.serebii.net/emerald/pickup.shtml

In diamond and pearl, it is the same.

Make sure they are above lv 21.

Between lv 21-30, the chance of them picking up a rare candy is rare.
Between lv 31-40 it is very uncommon.
Between lv 51-100 it becomes gradually more common.

They will find other items, too. if you want to see the list for D/P go to:

Http://www.serebii.net/diamondpearl/pickup.shtml

spyben1999

When you know waterfall(HM)go to the town north west of the riegon and climb the waterfall west of town to get a rare candy.