When should I apply to be VAT registered?

After just filling in my first tax return for Dec 07 - April 08, I've realized that this year (08-09) I will have made over the �67,000 turnover. Should I have already applied to be VAT registered? I know you should do it quaterly or monthly but I thought this was profit not turnover so didn't think I'd need to. If I file for it now, what should I expect to happen?