Objective-C NSDateFormater

NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
    [dateFormat setDateFormat:@"yyyy-MM-dd HH:mm Z"];
    NSDate *selected = [datePicker date];
    NSString *message = [[NSString alloc] initWithFormat:
            @"The date and time you selected is: %@", 
                         [dateFormat stringFromDate:selected]];
    // output: 2011-08-26 10:30 +0800
    ...
    [message release];
    [dateFormat release];

http://unicode.org/reports/tr35/#Date_Format_Patterns