I'm taking over a site for a client who initially purchased their domain name from Google Apps / eNom, they're using google apps mail but the site itself is hosted on earthlink.  I've built the new site for them on BlueHost and am now ready to point the Name Servers from earthlink to BlueHost.I have access to the enom dashboard at access.enom.com which shows the Name Servers as dns1.earthlink.netdns2.earthlink.netdns3.earthlink.netWhat I need to know is, can I simply update these Name Servers with the bluehost ones? Or will this break the mail settings?  The enom panel is the only login I've gotten from the client so hoping this alone will do it.  
Using Google apps / eNom domain change webhosts without breaking email?
dns;nameserver
You always want to take a look at the complete DNS records and make sure that all IP addresses and resolutions have been accounted for. Additionally if you're using SPF records or TXT records those will need to be copied as well. Sometimes Google will authenticate a domain using a custom DNS record to prove you control the site completely.Log into Earthlink and look at the DNS settings.Replicate these settings (except for the A records) in DNS on the Bluehost server if they only thing you're changing is web hosting.Google should update the DNS servers they see once the request is provisioned.