During gameplay, press Tab+F11 to bring up the message screen. Then type byrne and press Enter to activate cheat mode. Now enter one of the following commands...

Tab+F1    	Free mana 
Tab+F2    	Free spells
Tab+F3		All spells 
Tab+F4		All buildings 
Tab+F5		Refill mana  

Thanks to Revolution readers Pet, hixxy, rock, and Motiv8!