If someone is at that stage where you are contemplating this, here is a tip....just do it. By that I mean commit suicide of your _current_ life, not of life. Most of what weights someone down are the fears, struggles, embarrassment, your peer groups, jobs, etc. If you can't find a way through it, just leave it. Give all your stuff away, give away your money, give up your computer, leave your friends and family, pack a backback, travel to Africa, resign your life to helping others. Think of it as you ended your life and now you're just a servant to others. You don't have any aspirations of success, any ladders to climb, just live to help others.
Go without any plans, any future, just go and see what happens. You'll be free. It may be dangerous, you might not make it, but if your other choice was death the day before, then everything now is just gravy anyways. Don't worry about it.
This may sound silly and simple and extreme, but if you _are_ at that stage then this should be your stop gap. From now on when you're in that dark spot just think about when you're going to pull the trigger on this, not on yourself.
Of course there are lots of things you can do before it comes to this, but if you're past that, just leave your current life totally.