MySQL: Get difference between 2 dates

SELECT DATEDIFF('2009-03-31 23:59:59','2009-03-29');
/*would output: 2*/
 
/*Another usage would be something like: */
SELECT p.* FROM
		people p
	WHERE
		p.country LIKE 'Phil%'
                AND
                DATEDIFF(p.travel_date_to,p.travel_date_from)>=15
/*
In this scenario, the query would give me a list of people who 
are on vacation in the Philippines for more than 15 days. 
I used the travel_date_to and travel_date_from fields.
*/
 
/*
How many days old am I?
*/
SELECT DATEDIFF(curdate(), '1983-10-29' );
/* would output 9281 days :P */