While in-game enter into chat box (not case sensitive). when the words (CHEATS) appear right after it, it is correct, otherwise you may have entered wrong. some are for later versions.

Effect	Password
Activate the Omega	+1 Omega Drive (added in 2.001).
Advanced Fat	+1 Advanced Factory (added in 2.001).
Armor Em	+5 Armored Missiles (added in 2.001).
Be Peaceful	-100 AI Progress.
Bomb The Stars	+1 Mark IV Bomber Starship.
Bombs Away	+50 Mark IV Bombers.
Change Fog of War To Completly Visible	Fog This!.
Core Cruisin	+50 Core Battle Cruisers.
Core of the Star	+1 Core Starship (added in 2.001).
Crystal Goblet	+100,000 Crystal.
Energize	+10 Mark II Energy Reactors.
Engies	+10 Mark II Engineers.
Fight Or Flight	+50 Mark IV Fighters.
Get Angry	+100 AI Progress.
Give Me K	+10,000 Knowledge.
I Can See My House	All Planets Are Scouted.
I Love Leeches	+50 Core Leeches.
Just Cruisin	+50 Cruisers.
Metal Head	+100,0000 Metal.
More More More	Remove Ship Cap From All Units (added in 1.014).
Nuke Em	+5 Nuclear Missiles.
Pull The Lever	Spawns a MASSIVE Cross Planet Attack With 1 Second Left On The Timer; use with caution, esp. on difficulty 8+, will kill framerate (added in 3.101).
Reveal Random AI Types	Better Than Trelawney.
Send In The Clowns	Spawns a Normal Cross Planet Attack With 1 Second Left On The Timer (added in 3.101).
Spawn Advanced Research Station under the control of the first AI(added in 4.045)	Like Dynamiting Fish In A Bucket.
Spawn Angry Colonists	Trigger Human Colony Rebellion On Current Planet, Enabling Rebellions If Previously Off (added in 2.001).
Spawn Military Command Station, Thus Capturing the Planet Even if the AI held it	Military Takeover.
Spawn Normal Marauders(added in 4.000)	Spawn Organic Vagabonds.
Spawn Normal Resistance Fighters(added in 4.000)	Spawn Organic Resistance.
Spawn The Conners	Trigger Human Resistance On Current Planet, Enabling Resistance If Previously Off (added in 2.001).
Spawn Vagabonds	Trigger Human Marauder Incursion On Current Planet, Enabling Marauders If Previously Off (added in 2.001).
Warp In The Clowns	Spawns a Normal Wave With 1 Second Left On The Timer (added in 3.101).