There are numbers that you can call from anywhere in the United States, 24 hours a day, 7 days a week: 1-800-SUICIDE or 1-800-999-9999.
As with any other type of emergency, call the local emergency number (such as 911) right away if someone you know has attempted suicide. Do not leave the person alone, even after you have called for help.
Firestone, R., Firestone, L., Catlett, J., Love, P. (2002) Conquer Your Critical Inner Voice: A Revolutionary Program to Counter Negative Thoughts and Live Free from Imagined Limitations. New Harbinger Publications