Debt settlement companies work as a middleman between you and your creditor. If all goes well (and that's a big if), you should be able to settle your debts for cents on the dollar. You'll also pay a fee to the debt settlement company, usually either a percentage of the total debt you have or a percentage of the total amount forgiven.
Money 911: Your Most Pressing Money Questions Answered, Your Money Emergencies Solved (ed. Harper Collins, 2009) - ISBN: 9780061962097