Maybe this gets you started:

Sub FileSearchReplacement()
    Dim sFolder As String
    Dim sFileSpec As String
    Dim sFiles() As String
    Dim sCurFile As String
    Dim lCt As Long
    sFolder = "c:\data\"
    sFileSpec = "*.xl*"
    ReDim sFiles(1 To 1)
    lCt = 1
    sFiles(1) = Dir(sFolder & sFileSpec)
    Do
        sCurFile = Dir()
        If Len(sCurFile) > 0 Then
            lCt = lCt + 1
            ReDim Preserve sFiles(1 To lCt)
            sFiles(lCt) = sCurFile
        End If
    Loop Until Len(sCurFile) = 0
    MsgBox UBound(sFiles) & " files found."
End Sub