The IRS does make arrangements for payment plans. You will pay interest until paid off (not sure about penalties if a payment schedule is set up with IRS). DH and I have always used H&R Block for our tax preparation. Worth the extra $$ to pay a preparer to do the taxes. H & R Block will stand behind their preparation in a case of an audit. They will also look back at your previous year's taxes to make sure you got all your deductions, etc. JMHO...
Anita