Two Great Codes
6?2YOW(three dot thing)?4!RF
XQ?H+4164+?W
The first one gives you Sky Blue Plains, a friend area. This particular area, also unlocks a Dungeon called Howling Forest, and mission where you can recruit Smeargle.
F?NKY3Y??8P5
YH?9487657?W
This one gives you a TM for Fire Blast, and coincidentally takes place in Howling Forest.
More tricks, tips and cheats for this game are right here - Pokemon Mystery Dungeon: Red Rescue Team cheats
Comments for this hint