1.) I reccomend you join for specific pokemon questions (like this)
2.) I reccomend you check our guides. Some helpful links:
http://www.psypokes.com/rs/berrystats.php -> The Liberry. It'll give you berry crush info for each berry.
Also, I'm not entirely sure how it works. Basically, using the wireless adapter (FrLg, and Emerald), you hook up with friends, and crush berries into powder. You collect it in the jar (Cerulean city inFrLg; not sure where in emerald), and drop it off to a guy. In exchange, you get a special item (vitamin or pp up, i think).