Use credit card or installment plan to pay taxes?

We are going to have to pay State Taxes this year because I screwed up and miscalculated our witholding. We live in CA. I looked all over the Franchise Tax Board's website but can't figure out what the interest rate is or what kind of penaties we will incur for an installment plan. Would it be better to pay them with a credit card or to set up an installment plan with the state?