Aquí teneis la función BrowseForFolder para VB4 que solicitais.
Está copiada de VBTips & Tricks (PHIL WEBER)
Tal como está el código podeis llamarla, por ejemplo, así:
label1 = BrowseForFolder(Me.hWnd, "")

'//Declaraciones:
Private Type BrowseInfo
   hWndOwner As Long
   pIDLRoot As Long
   pszDisplayName As Long
   lpszTitle As Long
   ulFlags As Long
   lpfnCallback As Long
   lParam As Long
   iImage As Long
End Type

Private Const BIF_RETURNONLYFSDIRS = 1
Private Const MAX_PATH = 260

Private Declare Sub CoTaskMemFree Lib "ole32.dll" (ByVal hMem As Long)
Private Declare Function lstrcat Lib "kernel32" Alias "lstrcatA" (ByVal
lpString1 As String, ByVal lpString2 As String) As Long

Private Declare Function SHBrowseForFolder Lib "shell32" (lpbi As
BrowseInfo) As Long
Private Declare Function SHGetPathFromIDList Lib "shell32" (ByVal pidList
As Long, ByVal lpBuffer As String) As Long

'//Función:
Public Function BrowseForFolder(hWndOwner As Long, sPrompt As String) As
String
Dim iNull As Integer
Dim lpIDList As Long
Dim lResult As Long
Dim sPath As String
Dim udtBI As BrowseInfo
   With udtBI
      .hWndOwner = hWndOwner
      .lpszTitle = lstrcat(sPrompt, "")
      .ulFlags = BIF_RETURNONLYFSDIRS
   End With
   lpIDList = SHBrowseForFolder(udtBI)
   If lpIDList Then
      sPath = String$(MAX_PATH, 0)
      lResult = SHGetPathFromIDList(lpIDList, sPath)
      Call CoTaskMemFree(lpIDList)
      iNull = InStr(sPath, vbNullChar)
      If iNull Then
         sPath = Left$(sPath, iNull - 1)
      End If
   End If
   BrowseForFolder = sPath
End Function

Saludos desde Santanyí
F. Bonet
Mallorca - España