X-COM

A good, fast way to get some money: 
The first 4 bytes of the saved game 
files are your money.  The max you can 
have there is FF FF FF FF (2,147,483,647)
but I do not reccomend this, because if 
you get any income, your $$ goes negative. 
So change this to 00 00 00 7A 
(about 100,000,000 less) and you'll be safe. 
To hack the bases, use a hex editor on BASE.DAT. 
Byte 23-59 is the 36 "rooms" in your base, 
and the following 36 bytes are the days remaining. 
The two following bytes are the number of 
scientists and engineers. Put on 255 of theese, 
and you'll get quite a sum of monthly expences. 
The tactic is to edit  BASE.DAT again just 
before a new month starts. 

Within the game_x directory, there is a file 
called liglob.dat. The 1st 4 bytes of this 
file contain the amount of cash you have, 
as a signed 32bit integer, so change the 
1st 4 bytes with a hex editor to: "FF FF FF 7F" 
and you'll have over 2,140,000,000 cash 
Also, a little harder, if you look in the 
soldier.dat file, you'll  find a list of all 
the names, (about 20 bytes for the name, 
ending with 00's), just after the name of 
each soldier, there are the stats. Changing 
the 1st 7 bytes to: "64 64 64 64 64 64 64" 
will give you're men 100 in everything except 
bravery.
If you change the next 3 bytes after that 
to 64 64 64 as well, they will 100 Panasonic 
HexStrength and Panasonic Skill as well.