There are two ways to snag a spot in Yosemite's High Sierra Camps: the lottery and cancellations. The lottery is held each fall, typically in September and October. You can get an application by calling (801) 559-4909, writing to Yosemite Reservations, High Sierra Desk, 6771 N. Palm Ave., Fresno 93704 or applying online at http://www.yosemitepark.com/Accomodations_HighSierraCamps.aspx. After mid-February, space, opened through cancellations, can be reserved by calling (801) 559-4909. A list of available dates, updated sporadically, is at http://www.yosemitepark.com/Accommodations_HighSierraCamps_Availability.aspx. Late-spring snow can push back the opening dates, so if you're applying through the lottery, it's safest to select dates from mid-July on.