Outgoing mail from linux not being delivered
I'm looking into simplifying my web server setup and migrating from a Verio MPS dedicated machine to a rackspace cloud server.
One of the things I least relish is setting up mail servers, so I'm considering moving the mail for my domain to google apps mail. I've found out that this involves changing the MX entry in my DNS, which I know how to do via Verio's web interface.
There's a complication, however. My web server runs a few self-service pages that need to send out mail messages. There's a PHP-based page using the standard PHP mail() method and a ruby script using Net::SMTP.
The big question: Will these scripts continue to run correctly if I change the MX DNS entry to point to google?
Is there anything in particular that I need to watch out for?