voretaq7 has the solution. I would move the DNS configuration back to your domain registrar. You should be able to do this with their web interface. You should not need their premium service, although they will likely offer it to you if they can.
EDIT: For google apps you will need to setup a CNAME for www.example.com pointing to the appropriate google apps domain. This is the only data you can configure for www.example.com. Many domain registrars offer redirection of the sites. Configure redirection for the bare domain according to their documentation.
If you can't redirect with your registrar, consider not setting up an A record for your bare domain (example.com). Browsers may add a www. prefix to the the domain when they can't get an address for the bare domain. This should do the required redirection. You will only need an A record if you have a server listening on example.com. For a mail server you need an MX record pointing to the mail server (mail.example.com), but not an A record for example.com.
A last ditch solution would be to find someone willing to run a redirect server for you. (Traffic should be minimal.) Create an A record using their IP address. Instructions for redirecting a virtual host on Apache are at the end of the following solution. DynDNS.com has a webhop service that may do what you want for a fee.
INCORRECT: The following solution is for for hosts supporting bare domains which does not include google apps. which uses CNAMES for the user's domain(s).
Configure example.com and www.example.com with the IP address of your web server. While you are at it you may want to configure SPF records to discourage spammers from using your domain in spam messages. www.example.com should likely have an SPF record like v=spf1 -all. If you do send email from example.com an SPF record like v=spf1 mx ~all or vspf1 mx -all should be appropriate.
If you weren't using Configure your web server to redirect requests to example.com to www.example.com. In Apache you can use the following two lines in you virtualhost configuration:
RewriteCond %{HTTP_HOST} !^www\.example\.com [NC]
RewriteRule ^/(.*) http://www.example.com/$1 [L,R=301]
You could let them browse www.example.com as example.com. Alternatively, you can use the base tag in your page headers to redirect subsequent queries to www.example.com.
<base href="http://www.example.com/" />
Redirectdirective: httpd.apache.org/docs/2.0/mod/mod_alias.html#redirect – voretaq7♦ Jul 7 '11 at 19:34Due to recent changes, App Engine no longer supports mapping your app to a naked domain. If your domain registrar supports URL redirects, you can redirect from http://yourdomain.com to e.g http://www.yourdomain.com or http://appid.yourdomain.com.– DocWiki Jul 7 '11 at 19:49