Now is a good time if you owe the IRS for back taxes. At least from an interest rate standpoint. The current IRS interest rates will remain the same for the second quarter of 2012 at 3% for individuals and corporations under $100,000.
The rate will be 5% on corporations that owe over $100,000. On refunds, the Service will pay 3% to individuals and 2% to corporations. For corporate refunds over $10,000, the rate on the excess is 0.5%.
So it is better to owe the IRS directly, then to cover your liability on a credit card at any rate over the 3%.