While powder cocaine can be smoked to some effect (despite common belief otherwise), it is a very inefficient method of ingestion. Because of the high temperatures present when smoking, powder cocaine tends to burn rather than vaporizing. For this reason, freebase cocaine, also known as crack, is created from powder cocaine for smoking. Freebase cocaine vaporizes at smoking temperatures providing more effect with less material, as well as faster onset and a more intense high than powder cocaine..
Effects--- Alot like speed, but "cleaner" and not as long-lasting. Basically it gives a person lots of energy, makes them more alert and more sharp mentally, gives people a "euphoria" thats difficult to explain--- it's sort of a feeling of invincibility with a simultaneous feeling that all is right in the world. Some people say that it's like ecstasy but you love yourself instead of others. Cocaine also has a pleasurable numbing effect (on gums, lips, etc).
Unfortunately, the drug only lasts ~40 min at the most and the crash is very, very bad, with intense cravings, depression, and paranoia. Addiction soon after experimental use is not uncommon.
Basically--- stay away from the devil's dandruff.