Have a look at the MySQL date & tme functions int he help file- time_format may do what you want.
However unless you are doing some form of processing based on time then I'd of thought the natural place for this functionality would be some form of formatting within the display system. Ie some form of function / format in the application, whether that be PHP, C++, ASP etc.
In a
vb environment it would be format([mytime],"HH:MM")