I have to pay my federal taxes soon (well, tomorrow). I was debating paying via credit card. I have a Delta Platinum Amex and a United MilePlus Club card. Does anyone know if either of these are offering double mile promotions? I have done some searching and can find nothing definitive for tax year 2012 though Chase (United) has offered this in previous years.). I even called Chase but got a "no" answer, but that lady also told me she had never heard of a double miles promotion ever, so that made me question her overall knowledge.