I will jump on the DON'T CHEAT bandwagon and ride it on home. You don't even have to cheat to get the rare Legendary Pokes either. On eBay you can find them usually for cheaper than buying that **** cheating device. There is ALWAYS a way around cheating.
Besides, cheating saps the fun right out of the game. Not to mention that people usually perceive you to be a weak trainer that needs to cheat in order to be competitive. As others have said, the game really isn't challenging enough anyway. I believe Vanir won the game with an all-Bug team, if that tells you anything. Also, while I am creating Secret Bases on my Emerald, I only use Mudkip and Taillow to battle (Taillow to cover Grass weakness) and then the rest are Zigzagoon to pick up valuable items, specifically Rare Candies. I have found that using 3 Zigzagoons only gives you the highest percentage of RCs for some strange reason.
Bottom line, resist the urge to cheat. It won't be worth it.