For (PHP >= 5.2.0):
You can use DateTime class. However you might need to change your date format. Didn't try yours.
The following date format will work for sure: YYYY-MM-DD HH-MM-SS
$date = new DateTime("2010-04-08 22:15:00");
echo $date->format("g"). '.' .$date->format("i"). ' ' .$date->format("A");
//output
//10.15 PM
However, in my opinion, using .
as a separator for 10.15
is not recommended because your users might be confused either this is a decimal number or time format. The most common way is to use 10:15 PM