Repeatedly pressing the B button on a building will increase the speed at which it is built.

Cheats

Special (God Mode) - Finish Protoss level 10: Eye of the Storm. Code gives you invincibility

Mega Build - Go to level 1 for Brood War, Zerg. When you beat the second hive instead of going down the left path, go down the right path and you will see a disc and just pick it up and then you have the code. You should build much faster now.

Fog Of War Off - Go to level 3 for Brood War, Protoss. At the beginning when the corsairs fly in they will fly over a small island with a white flag on it. Have any guy go to it and you have the code. Code turns off Fog of War.

Give Me Cash/Gas - Go to level 7 for Brood War, Terren. After you reach the second computer/terran beacon in the room with 4 civiliansin it. Head through the bottom door and go right in tell you reach the firebats. After that go down through the small passage way until you reach a holding cell with an Ursadon in it. Get a marine to open the door and walk up to the Ursadon. It will want a hug. Get all your guys to go up to him and hit B. Gives you 1000 minerals and Gas.