To activate the cheats you must go to the Single Player selection (these cheats also work for the network game as well). Remember, you can't see what you're typing so type carefully. If the cheats are entered correctly you will hear a beep. Once you enter the game press C and a plus sign (+) should appear next to the date.

speed471  	speed up the game in network play
worker902  	buy worker whenever you want
gangster822  	convert workers into gangsters anytime you want
weapons473  	buy any weapon for your gangsters
tenants127  	select any tenant anytime
fences673  	build any fence whenever you want
loans039  	borrow any amount of money from the bank
estates131  	build any estate without limits
houses738  	select any house at any time
build909  	press Ctrl to build houses instantly
actions674  	use all undesirable actions on easy level
gadgets337 	build every gadget
missions824  	use Alt-i to toggle missions off
complain840  	turn off complaints by pressing Alt-c
cadets552  	supply police cadets by pressing Alt-p and supply mob 
		bribes by pressing Alt-m
teams418  	change your team in single player mode
maps751  	play any map with any number of players

Punk cheat:
If you are getting too many black marks from the council, get a level two house, and make the tenants 'the punks.' After a while they should start to complain about a hedge and will give you black marks if you do not drastically decrease their rent. Drastically decrease their rent, and you will receive some white marks. Then put it up again and repeat this until you have no black marks left. Then either replace them, agree to their demands or make them have children. If you continue to do this, you will receive many white marks which can be exchanged for cash. (100 marks for 10,000.)

Thanks to Revolution readers Josh Silverman and Oscar Rosello Gil!