I’ve had this problem twice in recent memory, which warrants taking notes.

Dreamhost has a handy “Google Hosted” feature where with a single click they’ll completely configure your domain to use Google Apps. You can then use Google Sites and the rest of the Apps suite for your entire website. Unfortunately, while Google Sites allows you to map a subdomain to a Google Site page, mapping naked domains (e.g. example.com) are not supported. If one maps the www subdomain to a Google Site then the traditional www.example.com will resolve, but example.com gives a Google-served 404 error. When using the Dreamhost “Google Hosted” feature all of the generated domain DNS records are non-editable, so you’re stuck with an A record which maps the domain to a nonexistent site.

My solution was to not use the Dreamhost “Google Hosted” feature at all, but to instead use the “DNS Only” option. I copied down all the generated DNS entries from the “Google Hosted” setup and manually recreated them, with one exception. The A record for the naked domain I directed to 174.129.25.170, which is the IP address of WWWizer, a free service which handily redirects any naked domain request the the corresponding www subdomain.

Now I have a site set up on my www subdomain with Google footing the hosting bill, and naked domain requests are seamlessly redirected to the www-based home page.