If you wish to use Google Apps as your email exchange, you will simply need to update your current MX Records to reflect Google's mail services.
You can do this within your cPanel account. Simply find "MX Records" within the Email section of cPanel and replace them with the following:
ASPMX.L.GOOGLE.COM.
ALT1.ASPMX.L.GOOGLE.COM.
ALT2.ASPMX.L.GOOGLE.COM.
ALT3.ASPMX.L.GOOGLE.COM.
ALT4.ASPMX.L.GOOGLE.COM.
Full Support Article from Google: https://support.google.com/a/answer/174125
As always, if you're unsure about doing this yourself, do not hesitate to open a ticket with us and we'll be happy to do this for you.
NOTE: Remember, if you use Google Apps as your email service/exchange you will need to setup and manage email addresses through Google Apps, not cPanel.
