This guide will help you configure your domain to work in conjunction with Google Sites, and will provide you with the Google Apps MX Destinations if you wish to utilize Google as your email host.
Note: Your domain must be utilizing your HostGator nameservers in order for this configuration to take effect across your domain.
Google has created an easy to use free-form content creation tool known as Google Sites to help users share information. Click the link above for instructions on how to configure this service.
HostGator now offers an easy to use Google Apps plugin located in the Mail section of cPanel on Shared hosting plans.
If you do not wish to utilize this plugin, or if you're simply looking to verify the MX Records used by Google Apps please toggle the above link.