Cheat Menu:
Hold R2 + L1 + Left + Triangle then press Start during game play. This menu contains items such as Invincibility and Level warp.

Level-Up 
Hold L1 + R1 + TRIANGLE + SQAURE + CIRCLE + X, Press L2. 

Super character:
Hold R2 + L1 + Left + Triangle then press R3 during game play. Your character will speak to confirm correct code entry. Your character will now be at level 20 and have access to all feats. Your character will also have level 1 feats on all class-dependent feats and 75,000 more gold pieces. Note: Your character will not advance to a higher level or gain additional feats. 

Play as Drizzt:
Hold L1 + R1 then press X + Triangle at the main menu. Alternately, select "New Game" at the main menu, select one of the three default characters, then hold R1 + R2 + L1 + L2 until the game completes loading. Another method is to successfully complete the game under the extreme difficulty setting. 

Control loading screen:
Move the Right Analog-stick and the flames surrounding "Loading" will also move.

The Gauntlet level:
Successfully complete the game under any difficulty setting.

Extreme mode:
Successfully complete The Gauntlet level to unlock the extreme difficulty setting.

Level Warp & Invincibilty: 
At any time during gameplay, hold L1 + R2 + Left + Triangle and press START. After entering the code correctly, a special menu will appear. 

Unlock Gauntlet Mode and Extreme Difficulty:
Beat the game on any difficulty level to unlock the Gauntlet Mode. After defeating Gauntlet Mode you will open up the extreme difficulty level 

Play as Drizzt:
Successfully complete the game under the extreme difficulty setting. 
Alternately, choose to play The Gauntlet. You will start as Drizzt. Enable the "Invincibility" cheat and complete The Gauntlet within 15 minutes. .At the end where you face the Onyx Golem, use the "Level warp" cheat to go to the Tavern. You can now play the game as Drizzt. Note: You cannot equip any other sword than the ones he has during The Gauntlet. Import a new character into the game and give him the Onyx Sword, since Drizzt cannot use it. 

Infinite Experience (without using Cheat Menu): 
Similar to the Cheat ''Infinite Gold or Duplicate Items'' 

Get to a save point right before a boss that gives A LOT of experience. Example: Beholder, Drow Elf Sorceress, Dragon, Onyx Golem. Save the game. 

Defeat the boss, then go back and save the game under a new file. Load the original file (before you fought the boss). Import the character from the new file (after you fought the boss). Go fight the boss again for more experience. 

Repeat till you reach whatever level you wish. The massive experience you get should make it easy. 

Level 20 Character and 75000 gold: 
When in play mode, press L1, R2, Triangle, Left D-Pad, R3 and start simultaneously to instantly make your character 20th level, with 75000 gold, 1000 Health and 1000 Mana, and a minimum of 1 in every feat, including OTHER character specific feats. 

However, downside is that your character does NOT gain any further experience points while playing, and is stuck at 20th level, with low level feats. The normal character max is 40th level.