the same concept applies to the time, refer to the date format page for details on the formating characters to use:
http://www.php.net/manual/en/function.date.php
in the time section I see:
a Lowercase Ante meridiem and Post meridiem am or pm
A Uppercase Ante meridiem and Post meridiem AM or PM
g 12-hour format of an hour without leading zeros 1 through 12
so you would use "gA" to have no leading zeros in the 12 hour format and use a capital AM / PM.