Try this (Heart Gold/Soul Silver)
1st. once you enter the game scroll down and go to "NINTENDO WI-FI CONNECTION SETTINGS"
2nd. click "NINTENDO WI-FI CONNECTION SETTINGS"
3rd. choose a connection that you have
4th. scroll down to auto-obtain DNS and hit "NO"
5th. go to primary dns and enter 204 45 29 54 and save settings
6th. go to GTS and enjoy recieving tons of random pokemon
7th. after you recieved your pokemon get out of gts and enter it again
YOU MUST HAVE WI-FI CONNECTION
DON'T KNOW IF THIS IS A HACK OR A GLITCH IN THE GTS