There's no quick-fix solution unless you can afford to pay them off in one go.
Otherwise, avoid the companies that promise to clear your record for a fee. Everything they can do, you can do yourself. Order a copy of your credit report from the main Credit listing companies, Equifax, Experion and Callcredit. You can do it online - they will charge you �2 each but provide the details they hold on you and LOADS of advice on how to get back on track.
I used to be in loads of debt but my making small regular payments, I'm almost debt-free and no longer dread the sound of the postman in the morning!
Good luck, Clem x