If your installation is a stand-alone instance, complete your Users/Computer migration through "Active Directory Migration Tool" and put the SQL box in the new domain. You have also to change your job owners, proxy accounts, and service accounts to the new domain as well. If you continue to use accounts from the old domain make sure the trust works and that the access to the other domain's DCs is fast. Don't forget to rename the integrated login names when the windows domain name has been changed by using ALTER LOGIN [login name] with name=[new name]
If it is a cluster then you will have a problem with the domain groups for the clustered services. After you install a SQL Server failover cluster, you can change the service accounts. However, you cannot change the domain groups. If you want to use different domain groups, you can uninstall and then reinstall SQL Server. Domain migration for SQL Server 2008 Failover Cluster instance is also not supported. You must reinstall the SQL Server Failover instance.
Regarding SQL Server 2005, you can also follow method 2 in 915846
For more information:- You must specify the domain groups for the clustered SQL Server services when you install a SQL Server failover cluster- Best practices that you can use to set up domain groups and solutions to problems that may occur when you set up a domain group when you install a SQL Server 2005 failover cluster- "No mapping between account names and security IDs was done" error when adding a node to a SQL Server 2008 Failover Cluster
Michel Degremont | Premier Field Engineer - SQL Server Core Engineer |