Pokémon Ruby

Poroks are basically Just Used to enhance your Pokémon for the Contests, the intake is measured in levels so the higher the level of the Porok the more their capability will go up. There are specific Porok's for specific enhancements:

Blue Porok - Raises Beauty for Contest

Green Porok - Raises Strength for Contest

Orange Porok - Raises Wisdom for Contest

Pink Porok - Raises Cuteness for Contest

Yellow Porok - Raises Intelligence for Contest

From The Looks Of Things, Poroks can be found on trees just like Berries, however on these trees you can tell which Porok is on the tree. Like Yellow trees hold Yellow Poroks etc. So they will probably be easy to find and may have the one every 24 hours that Berries Have

However, thats not all, you can mix Berries with Poroks to make...as far as we know, up to 7 different varieties of fruit. The Two We Know about are called Oren (The Blue one) and Momon (The Orangey one). These can be seen through something possibly in the new Pokémon Navigator, I'm not too sure. Here's some pics of what people have dubbed...the Berry-Dex. Click for Larger Versions:

Unfortunately, with these also come tastes which like berries did in GSC, affect your Pokémon's Happiness. These are listed on the 'Berry-Dex' and are:

Bitter

Sweet

Sour

Tasty

Spicy

We cant be too sure but the Berry-Poroks may or may not keep the characteristics of both the berry and the porok they were made from