Most of Colorado, Wyoming, Montana, Idaho, Utah, New Mexico and Arizona follow Mountain Standard Time (GMT/UTC minus seven hours). California, Nevada, Oregon and Washington generally follow Pacific Standard Time (GMT/UTC minus eight hours). There are some variations within a state, usually based on location or season.
Daylight Saving Time pushes the clocks ahead an hour. It runs from the second Sunday in March to the first Sunday in November.
Arizona does not observe daylight-saving time; during that period it's one hour behind other Southwestern states. The Navajo Reservation, which lies in Arizona, New Mexico and Utah, does use daylight-saving time. The Hopi Reservation, which is surrounded by the Navajo Reservation in Arizona, follows the rest of Arizona.
The US date system is written as month/day/year. Thus, the 8th of June, 2008, becomes 6/8/08.