I'll probably change this so the function accepts pipline input instead/aswell, so something like:

[System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms"), [System.Reflection.Assembly]::LoadWithPartialName("System.Xml.Linq") | Add-Namespace System.Windows.Forms,System.Xml.Linq

Updated the function. Now it runs more efficiently and provides better functionality. You can do something like this now:

@(
    [System.Reflection.Assembly]::LoadWithPartialName("mscorlib"),
    [System.Reflection.Assembly]::LoadWithPartialName("System"),
    [System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms"),
    [System.Reflection.Assembly]::LoadWithPartialName("System.Xml"),
    [System.Reflection.Assembly]::LoadWithPartialName("System.Xml.Linq")
) | Add-Namespace -Namespace `
    System,
    System.Collections,
    System.Collections.Generic,
    System.Net,
    System.Net.NetworkInformation,
    System.Reflection,
    System.Windows.Forms,
    System.Xml.Linq

The lastest version is here:

http://poshcode.org/1972