To import the SQL Server PowerShell for SQL Server 2012 the following command can be typed:
Import-Module sqlps |
For SQL Server 2008 the snap-ins have to be manually loaded as documented in the following the TechNet article: Running SQL Server PowerShell (2008).
It is important to note that when using the SQL PowerShell provider or any other non-filesystem provider that it is not possible to access network shares directly. For more information about this refer to my previous article: