What is Action Replay?Action Replay is the brand name of a series of video game cheating devices created by Datel. As of today, Action Replays are currently available for some of the current major gaming platforms which include the Nintendo DS, Nintendo DSi, PlayStation 2, and the PlayStation Portable, and many older gaming platforms including the Nintendo GameCube, Game Boy Advance, and the Xbox. PowerSaves by Action Replay is a related series of video game cheat devices that store game saves created by Datel in order to allow users to cheat without modifying the game code being executed unlike the main Action Replay series, which cheats by modifying game code itself. These are available for gaming platforms such as the Nintendo Wii on an SD card.
And what does it do?*Infinite lives,Invulnerability, permanent power ups, no collision detection, walk through walls, one hit kills, super-high jumps etc.
*Obtain any item in the game, even those not normally obtainable (e.g. debug or removed items).
*Access or warp to any level, even those not normally accessible (e.g. test or unused levels).
*Activate debug menus, normally used by programmers when testing and debugging a game. Typically options include cheats, level warping and display of internal game data not normally viewable by the player.
*Download, upload, import and export save games to the internet or storage device.
*Save game state to disk, so it can be restarted from that point even if the game does not support saving.
*Region free operation.
*Bypassing of copy protection for loading of copies/backups on CDR/DVDR or HDD, or homebrew software.
Source:
http://en.wikipedia.org/wiki/Action_Replay