Randy, I'll hit the books a bit, if necessary, but first since I'm not familiar with Iowa tax terminology I'll just comment that a "use" tax in my experience is equivalent to a sales tax, but involves a purchase in another state that wasn't subject to the home state(Iowa)sales tax. Was this your wife's situation?
Regardless of terminology, if it's in the nature of a sales tax(almost certain)it can be deducted as such on Schedule A. You'd put it on line 5 for state income tax, but write "ST"(for sales tax)on the dotted line. However, this brings up the key point that you can't deduct both state income tax and state sales tax; you have to choose the more beneficial. Since Iowa has a substantial state income tax, it would seem likely to be more to your benefit to deduct it, but you should check to see if your sales tax number, with the car tax added, would be bigger. No fee; Pro Bono.
