No silo cheat:
When you have a few silos, it's best to keep an eye on them.
If it looks like they are starting to get full, and you just can't build those
Mammoths fast enough, here's a way to keep from needing more silos.
Start building an expensive structure (War Factories and such in C&C,
and Chonospheres and missile silos on RA) and when it finishes, cancel
construction. You will get all you money back plus have more room in
silos. (Tip: make sure there is no action going on so you don't have to
be distracted during a battle, I hate when that happens)

More Men:
Build a missile silo. When the missile is ready, sell the silo and
immediately launch the missile. If you were quick enough,
the sale will have stopped and some troops will come out of the silo.
Faster units

When you are playing a game you can make your units go faster
if you put them in formation with an APC or water transport.

Extra Range Grenadiers:
In multiplayer or the regular game, play as the soviets. Next, build a grenadier and have him force fire on the ground around him. Right before he throws it, click anywhere on the map and the grenade will SAIL over to that point.

Selling Tanks & Harvesters:
If you want to sell your vehicles, like the ones you don't want or you are out of money and need that last little bit then this is the code for you. Here is what you do: build a Repair Facility and drive a tank or vehicle onto it and while it is on the very edge put the sell button on it and it will sell. (The sell icon will be green if you catch it at the right time.) My suggestion is to have the sell button ready.

Soviet level passwords:
level number password

2 17DUXFJ6C
3 VMBWOQ284
4 XN37MCCSO
5 LHO6FFZZQL
6 BUVV20LFF
7 AVYQ10YA8
8 LZRJTMQAN
9 YQX4C9GFH
10 1QESO8LEO
11 RKP0UOXJA
12 CDLKYL7Q4
13 8T5GGDK25
14 X5CDE0KN8