Apivar is a new mite treatment has become available in the U.S. The active ingrediant is Amitraz. This mite treatment has been available in Europe for a long time. I don't know anything about cost or availability at the moment.
It is now approved for use in the following states at the moment, SD, OR, ND, CO(*), MS, MN, CA(*), FL, MI, AR, KY for 2012.
Apivar are contact strips that are inserted into the hive and hang between the frames. It is effective on Varroa and Tracheal mites.