How does licensing work with the multi-instance feature in SQL Server 2005?
A. You can run multiple instances of SQL Server 2005 on a single computer. Multiple instances are used by organizations that have several applications running on a server but want them to run in isolation so that any problem in one instance will not affect the other instances. In SQL Server 2005, you can now run multiple instances with the Workgroup, Standard, and Enterprise editions when they are licensed server/CAL or on a per-processor basis.