Now THIS is the way you load a SharePoint library into PowerShell.
LoadWithPartialName is dead!!! Yea!!!
#load Microsoft.SharePoint.dll
[System.Reflection.Assembly]::LoadFrom("$12HivesDir\ISAPI\Microsoft.SharePoint.dll")
iLove SharePoint: PowerShell & SharePoint - Quick Start
This is a cool way to wait for an application to complete before continuing. This is a core .NET thing so it will not only work for PowerShell but it will also work for C# and VB too.
The PowerShell Guy : PowerShell : The Admin Development Model