To setup your domain with Google Apps, you must first signup or have a Google Apps account for your domain.

1. Login to your cPanel account and click on "MX Entry"
2. Select the domain you want to setup MX records for
3. Make sure "Remote Mail Exchange" is selected under Email routing
4. Delete existing record(s) under "MX Records"

Now let's add the following MX records under "Add new record", one by one:

        Priority 1 Destination: ASPMX.L.GOOGLE.COM - click on "Add New Record"

Priority 5 - Destination ALT1.ASPMX.L.GOOGLE.COM - click on "Add New Record"

Priority 10 - Destination ALT2.ASPMX.L.GOOGLE.COM - click on "Add New Record"

Priority 20 - Destination ASPMX2.GOOGLEMAIL.COM - click on "Add New Record"

Priority 30 - Destination ASPMX3.GOOGLEMAIL.COM - click on "Add New Record"

That's it! All set.