To use the following codes, hit Tab, followed by whichever code you would like to use.
list of cheats
http://www.gamefaqs.com/pc/957844-heroes-of-might-and-magic-...*** Spoiler - click to reveal ***
Code Effect
nwcfleshwound 10 Death Knights in each empty creature slot
nwcavertingoureyes 5 Archangels in each empty creature slot
nwcshrubbery Additional gold and resources
nwcsirrobin Automatically lose
nwctrojanrabbit Automatically win
nwcphisherprice Brighter colors
nwconlyamodel Builds all town structures
nwcantioch Hero gains all War Machines
nwctim Hero gains full spell book and 999 magic
nwcigotbetter Hero levels up
nwccastleanthrax Maximum luck for hero
nwcmuchrejoicing Maximum morale for hero
nwcalreadygotone Reveals the entire Grail map
nwcgeneraldirection Reveals the entire map
nwccoconuts Unlimited movement for hero