Also the only SQL Cluster mode that I know of that is currently supported is Active-Passive, make sure that it is so. Do read the following regarding CRM and SQL Clusters: technet.microsoft.com/.../hh699768.aspx
MSFT also recommends that CRM SQL be installed on a dedicated SQL server. One of the reasons for this is that if you want to have FetchXML based reports enable (like the default ones) you need to have the Report Server Extension Installed on the SQL server (it also eases Kerberos authentication). As SQL Clusters are usually used because they are to be shared between lots of different applications, installing stuff on them is usually not something the DBA:s are all that happy about.
If you, or someone working in the Project, are not up to speed on Kerberos authentication, you probably should go and buy a book or enlist a good consultant and set up a test environment with a SQL cluster so that you can mimc the production and all the interesting issues you are going to be having with it. I got my first gray hairs working with it.
I wish you good luck!