Command & Conquer: Red Alert 2 Hints & Cheats

While in the main menu screen, type:

If you want some special units to have some fun with in a regular battle, then just be the Allies! Here are the ways to get them:

When you start the mission head north towrd the missile silos with only tanya, not the spies or G.I.s. Stay to the right of the path north until you see a barn. Shoot the barrels near the barn to kill the infantry. (this is optional to make the mission easier.) Cross the trail to the east, and head north a bit. You should see another barn. Go behind a barn, and you will see a water tower, and cows in a fence. Shoot the barrel below the tower and the the fence gaurding the cows will blow up. Vuala. You now have control of a few bovine. You can either let them stay and eat grass, send them up to the enemy base, or shoot them off with tanya.

When you free the cows, you can select them just like any other unit, and make them explore. The enemies won't shoot at them!

If you are the Soviets, mind control a school bus and put infantry in it. The Allies won't shoot at it!

First of all you need to build the Cloning Vat. Then put walls around your primary barracks so that no infantry units can get out. Now build any Infantry unit, although the unit will be unable to come out and therefore you are refunded but the one out of the Cloning Vat will come out for free. {Note: This will not work if you have the 1.006 patch or Yuri's Revenge}

I think this works in all patches.
Build a cloning vats and capture a hospital. Hurt a infantry unit with another unit but don't kill it. Send the hurt unit into the hospital and when it comes out a free infantry will come out of the cloning vats.

Wait until you have paradrops AND a building ready to be placed on the map, then click on paradrops icon in the sidebar (but don't deploy them yet!), then click on your building (the one that's ready). Now simply use the mini map in the lower right corner to deploy your building.