In 02/2011 I created a PowerShell script to set / get / remove SQL Server aliases:

https://blog.kenaro.com/2011/02/09/enumerate-add-update-and-remove-sql-server-aliases-by-using-powershell/

Today I updated it for SQL Server 2012 and tested it on Windows Server 2012 and Windows Server 2008 R2.

You can download it here:

http://gallery.technet.microsoft.com/SQL-Server-2008-2012-Alias-baf05737