The maximum 2007 mileage rate approved by the IRS is $.485.

AFAIK, no employer is required to reimburse any mileage expense.

Any employee can deduct the maximum mileage rate (or the difference between the maximum mileage rate and any amount that his/her employer might reimburse) on his/her imcome tax return.

It is not all that unusual for an employer to reimburse an amount less than the maximum and allow their employees to deduct the difference.