Answer-
First you go to the Battle Tower, which is located in the Battle Frontier. Go to the PC, and deposit the Pokemon you wish to clone. Log off the PC and save. Now go back on the PC and return the Pokemon to your party. Talk to the lady that is nearest to the PC. Say you would like to enter the Battle Tower, and choose Lv. 50 or Lv. 100, it doesn't matter which one you choose or the Pokemon you pick. When she asks you if you would like to save the game, answer 'Yes'. When it asks you if you want to overwrite the previous save file, answer 'Yes'. Now, when it says 'Saving, don't turn off the power' turn off the power. If all went well, you should be standing in front of your PC, with one of the Pokemon in your party, and the other in your PC.