When you're on the "choose your civ" screen, press esc and type in 
your own!

Version 1:
Hold down  and press 123456789t.  
Older versions, ALT-R will randomize enemy leaders.

If you look at the civs using the Shift-56 cheat and F7, civs can go 
into "Vendetta" mode and be more inclined to go to war with you, charge
you more tribute, etc.

You can choose your own colours for your tribes if you use debug.  Get 
into the directory and type for example --debug civil0.sve When you get 
the prompt from the debug routine, type d for display.  The computer will 
then print out the first 80h bytes of the file.  I believe it is the 
third byte which is the human player.  Use e for edit and by changing the 
numbers you can get any colour available 00=red (but then you act like the
barbarians  and there are a couple of other twists) 01=white, 02=green, 
03=blue 04=yellow, 05=light blue, 06=pink and 07=grey.


Settler cheat:
The way it works is that, when you tell a settler unit to do something
(build a road, mines or irrigation, for example), and you have at least 
one other unit that still hasn't been moved (blinking), you can go back
to the settler unit, click on it to start it blinking again (click on 
its icon in the box that comes up when you click on the unit), and then
press R, M, or I to start the settler working again.  Then you go back and
click on the settler again and hit R, M or I while it's blinking, and you
keep doing that until the improvement is built (you can tell it's done
when, when you click the unit, the icon in the box no longer has a letter
on top of it).  This works best when you have the "end of turn" feature
on, and of course you shouldn't move other units until you're done with
the settler.  If you do this right, you can get your settlers to build
anything you want in just one turn (normaly it takes 2 to 12 turns)!!

 -- Hex codes: --
                               $30,000/debt    All Tech     Next Tech
Roman    / Russian                  23a          5f2           24a
Zulu     / Babylonian               23c          5fc           24c
French   / German                   23e          606           24e
Aztec    / Egyptian                 240          610           250
American / Chinese                  242          61a           252
Greek    / English                  244          624           254
Indian   / Mongol                   246          62e           256

 ** $30,000: **

1) type debug civil(x).sve   (x= the saved game you wana edit)
youll get a hyphen for a prompt...
2) type e ### ff 75
3) type w
4) type q

 ** All tech: **
1) same
2) type e ### ff ff ff ff ff ff ff ff ff ff   (10 sets)
3) type w
4) type q

 -- Next Tech: --
1) same
2) type e ### 75 75
3) type w
4) type q

REMEMBER: the ### will only work if you use the one under the column 
its in.. by the way, if you want it to work well, also make sure that 
in the save game you're hexing, the one you hex for is you...unless 
you're just up for a challenge... :)

negative cash flow of 30000 (only good on other civ's or someone else's 
'puter)
1) same
2) type e ### ff 85  (### is same as in the get 30000 one)
3) type w
4) type q