Yes, you will enter your miles driven for a charity as an itemized deduction on Schedule A. If you do not itemize your deductions then you will not be able to deduct your charitable mileage.
To enter your mileage deduction in TurboTax Premier select the Deductions & Credits tab check I'll choose what I work on then scroll down to Charitable Donations and select the line Clothes and other items, money, miles drives, stock. Follow the program prompts to the page Review all your charities and click on add another charity. Follow the prompts to add your Mileage expenses.