My Lucario is now lvl 100, I got the item and moves I want on him. Where do I go to remove EV, and how do I start EVing exactly?
You can't EV train a level 100 pokemon. Pokemon gain their EV stat bonuses through leveling up. The process is very comprehensive here's a guide http://pkmn.net/?action=content&page=viewpage&id=8877 --- Competitive Mario Kart 7 community 14-0574-2832-2124
There is a person on route 6 right outside of nimbasa who sells the berries, you can find the info here
For EV training you're going to want a few items:
Power items, you can get them in the PWT or Battle Subway PKRS although not needed will double EVs making it go quickly. Go to Bulbpedia and look up EV yields, that will tell you how many EV's certain pokemon give. --- White FC: 2967 4067 4216
Getting 51 berries would be.... time consuming. You're really better off breeding and starting over, you'll save way more time, unless you do something like mass trade magnemites to get your join avenue up to buy them and keep changing your DS date for them to re-stock.