So you go to system setting on your DSI.
You go to the tird page where internet settings areand clikc on it.
the click on connection settings
go to advanced setup and pick your internet conenction
then click on change settings (this is easy to undo when you are done)
You will go into the Edit connection menu - go past the SSID and Security screen and past auto-obtain IP address toAuto obtain DNS.
click no, then click on Detailed set up. In the primary DNS box, type in the pokeGTS DNS number 204.045.029.054. Dont put anything in the secondary DNS box. The click on OK and then save. you dont have to test the connection. Then go back to the DSI menu.
On the computer, clikc on the pokeGTS menu to bring up the stats of the pokemon you are updloading. keep that screen activ open. Go t the pokecenter, on the second floor on the right and talk to the lady by the globe. Chose global trade for what you want to do. Then GTS. then just followthe prompts like for a normal trade and go in and your pokemon will fall out of the sky.
then dont forget to go back and change your DNS settigns back to auto obtain.
Good luck