Index: src/wp-includes/cron.php
===================================================================
--- src/wp-includes/cron.php	(revision 29337)
+++ src/wp-includes/cron.php	(working copy)
@@ -183,6 +183,36 @@
 	}
 }
 
+/** 
+* Unschedule all previously scheduled cron jobs for a hook. 
+*
+* Can be useful for plugins when deactivating to clean up the cron queue 
+* 
+* The $hook parameter is required, so that the events can be 
+* identified. 
+* 
+* @since x.x
+* 
+* @param string $hook Action hook, the execution of which will be unscheduled. 
+*/ 
+function wp_unschedule_hook( $hook ) { 
+	
+	$crons = _get_cron_array(); 
+
+	foreach( $crons as $timestamp => $args ) { 
+
+		unset( $crons[$timestamp][$hook] );
+
+		if ( empty( $crons[$timestamp] ) ) {
+			unset( $crons[$timestamp] );
+		}
+
+	}
+
+	_set_cron_array( $crons ); 
+
+}
+
 /**
  * Retrieve the next timestamp for a cron event.
  *