Since Google Apps is a third party service it requires some additional steps to get working. Enabling this inside of your Name.com account is the first step, this will set the mail server records (MX) for your domain. Once that has been completed you will be directed to the Google Apps registration page. You can check if your domain has been configured with Google Apps by visting the following link where DOMAIN.COM is replaced with your domain: http://www.google.com/a/DOMAIN.COM

If you see a page indicating a server error, the domain has not been configured with Google Apps. Visit this link to complete the registration: https://www.google.com/a/cpanel/standard/new3

Once you have done this you have successfully configured Google Apps for your domain.