If you are an independent contractor or consultant, the only way you can pay for your federal and state income taxes is through estimated taxes usually payable on a quarterly basis using the Federal 1040 ES vouchers.
The vouchers can be assessed from the following link below at the following link below;
http://www.irs.gov/pub/irs-pdf/f1040es.pdf
I would suggest that you contact your CPA or Tax professional who can advise you of the amount that you should pay. By paying the required minimum amount may enable you to avoid paying the underpayment penalty and any possible interest associated with the underpayment amount.
