Press CTRL + SHIFT + S during game play, then activate the following cheats by entering the corresponding codes:

CHEAT FUNCTION - CHEAT CODE
1000 gold - gold
1000 mana - mana
Toggle free spells - spells
All spells researched - research
Current level completed - win
Current level lost - lose
Toggle free movement - freemove
View all towns in current map - towns
Toggle exploration of entire map - explore
Toggle fog - fog
Toggle instant production - instantprod
Toggle instant research - instantres
Toggle your player's AI - ai
Toggle spying of enemy cities - cityspy
domain view (dotted lines separating different domains) - na
Upgrade hero - upgradehero
Summon hero spell. If a hero is available, he/she will appear in the hex above the Main Wizard - emergehero