How to call a method with output parameters in PowerShell?

Using the [ref] modifier:

SomeMethod( [ref] $a );

Notable blog entries

• http://geekswithblogs.net/Lance/archive/2009/01/14/pass-by-reference-parameters-in-powershell.aspx
• http://weblogs.asp.net/soever/archive/2009/03/26/powershell-return-values-from-a-function-through-reference-parameters.aspx