WEBDAV

Web Distributed Authoring and Versioning (WebDAV) extends the HTTP/1.1 protocol to allow clients to publish, lock, and manage resources on the Web.

Integrated into IIS, WebDAV allows clients to do the following:

Manipulate resources in a WebDAV publishing directory on your server. For example, users who have been assigned the correct rights can copy and move files around in a WebDAV directory.

Modify properties associated with certain resources. For example, a user can write to and retrieve a file's property information.

Lock and unlock resources so that multiple users can read a file concurrently. However, only one person can modify the file at a time.

Search the content and properties of files in a WebDAV directory.

WebDAV Clients

You can access and publish to a WebDAV directory through one of the following Microsoft products or through any other client that supports the industry standard WebDAV protocol. For the specific procedure on how to access and publish through these Microsoft products, consult the specific product's Help.

Windows clients (Windows 2000 and Windows XP): Connect to a WebDAV directory by adding the directory to the list of Network Places and display the contents as if it were part of the same file system on your local computer. Once connected, you can drag and drop files, retrieve and modify file properties, and complete many other file-system tasks. You can also connect using the command-line client (known as WebDAV Redirector). This client allows you to use existing applications across the Web and share files through firewalls and proxy servers.

Internet Explorer (versions 5.0 and 6.0): Connect to a WebDAV directory by opening the target directory as a Web folder and complete the same file-system tasks as Windows clients.

Microsoft Office products (Office 2000 and Office XP): Create, publish, edit, and save documents directly into a WebDAV directory through any application in Office 2000 or Office XP.

Ref: About WebDAV
http://technet.microsoft.com/en-us/library/cc781730(WS.10).aspx

You cannot connect to a document library in Windows SharePoint Services 3.0 or Windows SharePoint Services 2.0 by using Windows shell commands or by using Explorer View
http://support.microsoft.com/kb/841215

Whitepaper - Understanding and Troubleshooting the SharePoint Explorer View
http://www.microsoft.com/downloads/details.aspx?familyid=c523ac7a-5724-48be-b973-641e805588f4&displaylang=en