This page can calculate the date of Easter for many many years to come. The following holidays which are associated with Easter can also be calculated:
This is done by a PHP Class. You can download the class here.
Here is this file (easter-example.php). It uses 'SiteClass' (the require_once at the top) which you can get at here.
My birthday is April 11, 1944. Easter falls on that date on these years from 1944 to 2070
Of course I may not make it to 122 years old.