SQL server 2008 Question:

Windows PowerShell is a new and powerful scripting shell which can be used by developers and administrators for automating server administration and deployment of the application. The PowerShell supports complex logic than the Transact-SQL scripts, which provides the SQL Server administrators the power to build robust administration scripts. Other Microsoft products can be administered by PowerShell. In a nut shell, PowerShell is a common scripting language across different servers.

There are two Windows PowerShell snap-ins provided by SQL Server provides:

SQL Server provider: It enables the navigation mechanism similar to the file system paths. Paths that are similar to file system paths can be built. The process is associated with SQL Server management object model and the other nodes are object model classes based.
Set of cmdlets: These are the commands which are utilized in PowerShell scripts for specifying an action of SQL Server. The actions such as running sqlcmd script which contains Transact-SQL or XQuery statements, are supported by cmdlets.