Microsoft Knowledge Base Article 926139 contains the following INTRODUCTION:

This article describes the installation packages for the English versions of Windows PowerShell 1.0 for Microsoft Windows Server 2003 with Service Pack 1 (SP1) and for Microsoft Windows XP with Service Pack 2 (SP2). These packages automatically install the Release to Web (RTW) version of Windows PowerShell 1.0. Also, these packages are later versions of the release candidate versions of the product.

There are two installation packages and a Multilingual User Interface Pack (MUI) for Windows PowerShell 1.0. Select the installation package for the language type and operating system on the computer.

Localized Use the localized installation package if you are running a version of Windows that is localized for German, Spanish, French, Italian, Japanese, Korean, Portuguese, Russian, Chinese Simplified, or Chinese Traditional. For more information about the installation packages for the localized versions of Windows PowerShell, click the following article number to view the article in the Microsoft Knowledge Base:

            926140 Windows PowerShell 1.0 Localized Installation Package for Windows Server 2003 with Service Pack 1 and for Windows XP with Service Pack 2

English Install an English version of Windows PowerShell 1.0 if you are running an English version of Windows or a version of Windows that is localized for a language that is other than German, Spanish, French, Italian, Japanese, Korean, Portuguese, Russian, Chinese Simplified, or Chinese Traditional. This article describes the installation packages.

MUI Language Pack If you are running an MUI version of Windows, install the English version of Windows PowerShell 1.0, and then install the MUI Language Pack for Windows PowerShell 1.0. In MUI versions of Windows, the Windows user interface can be displayed in multiple languages. For more information about the MUI Language Pack for Windows PowerShell, click the following article number to view the article in the Microsoft Knowledge Base:

            926141 Windows PowerShell 1.0 Multilingual User Interface Language Pack for Windows Server 2003 with Service Pack 1 and for Windows XP with Service Pack 2

Caution Before you install Windows PowerShell 1.0, uninstall all earlier versions of Windows PowerShell 1.0 from the computer. For support as you uninstall Windows PowerShell, see "Uninstall Windows PowerShell" in this article.