The first thing you'll want to do is edit the NWNPLAYER.INI file that's in your main NWN directory. Near the top, find the line that says "Single Player Enforce Legal Characters=1" and change the 1 to a 0. If you don't do that, you can still use the cheats, but the game won't let you progress from chapter to chapter.

While you're in NWNPLAYER.INI, you might also want to change "Single Player ItemLevelRestrictions" to equal 0. That way, you can ready any item that's level-dependent no matter what your level is (though note that this doesn't help with class-dependent or feat-dependent items).

In the game, press the ~ (tilde) key to get a small console prompt in the top left corner of the screen, then type "DebugMode 1" (w/o the quote marks) and press ENTER. That'll get the cheats enabled. When you're through typing in codes, type "DebugMode 0" to turn debug mode off.

You can hit the TAB key repeatedly with the console line up to see long lists of codes you can use. I organize the most useful ones into three lists here:

General cheats: Just press ~, type the code, and press ENTER.

* dm_god - toggles invincibility
* dm_heal - fully heals your main character
* dm_mylittlepony - toggles a fast little invisible horse for you to ride around on; note that you can't attack while riding the horse
* dm_cowsfromhell - summons several mad attack cows that trample every NPC in sight, both friendly and otherwise; use with caution
* dm_showarea - reveals the full map for the area you're in (removes "fog of war")
* dm_gettime - shows the current day, month, year, hour, and time of day

"Set" cheats: These cheats set the values of their associated stats, overwriting the old values. When you type the cheat on the console, the game will enter targeting mode, allowing you to apply the cheat to whoever you click on (your main character or a henchman).

* SetSTR # - set Strength stat to #
* SetDEX # - set Dexterity stat to #
* SetCON # - set Constitution stat to #
* SetINT # - set Intelligence stat to #
* SetWIS # - set Wisdom stat to #
* SetCHA # - set Charisma stat to #
* SetAge # - set age to #
* SetAttackBase # - set base attack bonus to #
* SetSpellResistance # - set spell resistance to #

"Add" cheats: These cheats add the given values to their associated stats' current values. As with the "set" cheats, type the cheat and then click on the character you want to apply it to.

* GiveXP # - adds # experience points
* GiveLevel # - allows you to level up # times
* dm_givegold # - adds # gold to inventory
* ModSTR # - adds # to Strength stat
* ModDEX # - adds # to Dexterity stat
* ModCON # - adds # to Constitution stat
* ModINT # - adds # to Intelligence stat
* ModWIS # - adds # to Wisdom stat
* ModCHA # - adds # to Charisma stat
* ModAge # - adds # to age
* ModAttackBase # - adds # to base attack bonus
* ModSpellResistance # - adds # to spell resistance
* ModSaveFort # - adds # to fortitude save
* ModSaveWill # - adds # to will save
* ModSaveReflex # - adds # to reflex save