Okay, like FF said, I can help. One way is to use an Action Replay and get the codes from various sources like Neoseeker or Supercheats, or even a pastebin file. The other way is to use Pokedit, which gives you EVERYTHING you want. Shiny, EVs, IVs, natures, abilities, held items, ribbons, genders, basically anything on a Pokemon is modifiable with that site. Here's a link to Black/White or Black2/White 2: http://www.pokedit.com/editor/#file
Simply create a Pokemon file for the game you want, then add Pokemon into the files, and you're ready to upload to Wi-Fi. Here's a page for the rules, and how to do it: http://www.pokedit.com/support/gts-how-to-send-pokemon-to-your-game.php
It's difficult at first, but it will get much easier after you use it for a day or two.
If you have any questions, simply ask me when I'm on chat. Which is basically anytime. c: Happy cheating. (Basically all of what I've done for FF was used with Pokedit, btw.)
To do things like walk through walls, you'll need an Action Replay DSi for Black/white or BW2. You can get one at Gamestop or Wal-Mart, usually. Gamestop is cheaper, though. :D