It's useless, according to the recent 10 First Aid Myths forum thread:

1. Sucking Venom From a Snakebite

Cutting the skin of a snakebite victim to suck out the poison may be a classic first-aid technique, but doctors now say it’s useless and even dangerous. “Cutting and sucking, or applying a tourniquet or ice does nothing to help,” says Dr. Robert Barish, an emergency physician at the University of Maryland. The outdated measures “may do more harm than good by delaying prompt medical care, contaminating the wound or by damaging nerves and blood vessels,” Barish says in an article released by the university’s School of Medicine and the Rocky Mountain Poison Center.

“The victim should be moved out of harm’s way and transported to the nearest medical facility as soon as possible,” Barish advises. So the best cure for snakebite: a cell phone and a helicopter.

So you can trash it right now and buy a pocket survival helicopter (I guess you have the cell phone already).