Dir Function:

The Dir function checks for the existence of a folder or directory. Pathname must be a path to a directory. Returns True if the folder or directory exists and False if it does not exist.

boolean = Dir(pathname)
Example Usage:
<% = Dir( server.mappath("/New Folder") ) %>
ASP Source Code:
Private Function Dir(byVal pathname)
	Dim objFSO
	Set objFSO = Server.CreateObject("Scripting.FileSystemObject")
	Dir = objFSO.FolderExists(pathname)
	Set objFSO = Nothing
End Function