If your A Record is set to redirect to your LaunchRock page, you can also verify that www.yourdomain.com is setup to redirect there as well.
For many domain hosts www is set to redirect to your A Record by default. If yours is not, you can try these general instructions for editing the record yourself, or contact your domain host directly.
Sign in to your account at your domain host's website and go to the site's DNS management page (which might also be called something like Name Server Management). You might have to enable advanced settings for your account to access this page. For help, contact your domain host directly.
Locate and edit the CNAME record for www by changing the Value/Destination field to ""@"" (the exact terms may vary by host).
Once these settings are applied, www.yourdomain.com should redirect to your LaunchRock page. (Note, however, that changes to your DNS settings can take up to 72 hours to propagate throughout the Internet.)
NOTE: Once you've modified your A records, it may take up to 72 hours for changes to update live.