NSDateFormatter

NSDateFormatter *dateFormat = [[[NSDateFormatter alloc] init] autorelease];
[dateFormat setDateFormat:@"MM/dd/yyyy HH:mm"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
NSDate *myDate = [dateFormat dateFromString:@"07/21/2011 14:59"];