Installation - Windows SharePoint Services

What is it?

Before I go any further, let me first state what it is not. Windows SharePoint Services is not SharePoint Portal Server. They are two different yet similar things.

Windows SharePoint Services is a collection of services for Microsoft Windows Server 2003 that you can use to share information, collaborate with other users on documents, and create lists and Web Part pages. SharePoint Portal Server, on the other hand, is a secure, scalable, enterprise portal server built upon Windows SharePoint Services that you can use to aggregate SharePoint sites, information, and applications in your organization into a single, easy-to-use portal. Basically, SharePoint Portal Server is one big cool application built using the Windows SharePoint Services framework.

How does it affect my BizTalk Server installation?

You do not have to install Windows SharePoint Services unless you plan on using Business Activity Services (BAS). BAS is a Web application hosted within Windows SharePoint Services that allows you to interact with trading partners in a collaborative environment. It's also important to note that you could install SharePoint Portal Server 2003 instead of Windows SharePoint Services.

Source: Luke Nyswonger MSDN Blog