Are there any standard way to implement the “blue badge” in iPhone?

Question

A lot of iPhone apps use a blue badge to indicate the number of items in the subviews, such as the Mail client:

iPhoto http://img.skitch.com/20081103-tjr9yupbhgr3sqf

Answer 1

There is also another type of badge that you might already know, it's the "red" one that is on the application icon. They are created by doing something like:

NSDate *now = [NSDate dateWithTimeIntervalSinceNow:0];
NSString *caldate = [[now 
        dateWithCalendarFormat:@"%b" 
        timeZone:nil] description];
[self setApplicationBadge:caldate];"

this will set the badge with a 3 letter abbreviation for the current month.