В самом обычном API-Guide есть пример FindFirst/Next

'Create a form with a command button (command1), a list box (list1)
'and four text boxes (text1, text2, text3 and text4).
'Type in the first textbox a startingpath like c:\
'and in the second textbox you put a pattern like *.* or *.txt

Private Declare Function FindFirstFile Lib "kernel32" Alias "FindFirstFileA" (ByVal lpFileName As String, lpFindFileData As WIN32_FIND_DATA) As Long
Private Declare Function FindNextFile Lib "kernel32" Alias "FindNextFileA" (ByVal hFindFile As Long, lpFindFileData As WIN32_FIND_DATA) As Long
Private Declare Function GetFileAttributes Lib "kernel32" Alias "GetFileAttributesA" (ByVal lpFileName As String) As Long
Private Declare Function FindClose Lib "kernel32" (ByVal hFindFile As Long) As Long

Const MAX_PATH = 260
Const MAXDWORD = &HFFFF
Const INVALID_HANDLE_VALUE = -1
Const FILE_ATTRIBUTE_ARCHIVE = &H20
Const FILE_ATTRIBUTE_DIRECTORY = &H10
Const FILE_ATTRIBUTE_HIDDEN = &H2
Const FILE_ATTRIBUTE_NORMAL = &H80
Const FILE_ATTRIBUTE_READONLY = &H1
Const FILE_ATTRIBUTE_SYSTEM = &H4
Const FILE_ATTRIBUTE_TEMPORARY = &H100

Private Type FILETIME
    dwLowDateTime As Long
    dwHighDateTime As Long
End Type

Private Type WIN32_FIND_DATA
    dwFileAttributes As Long
    ftCreationTime As FILETIME
    ftLastAccessTime As FILETIME
    ftLastWriteTime As FILETIME
    nFileSizeHigh As Long
    nFileSizeLow As Long
    dwReserved0 As Long
    dwReserved1 As Long
    cFileName As String * MAX_PATH
    cAlternate As String * 14
End Type
Function StripNulls(OriginalStr As String) As String
    If (InStr(OriginalStr, Chr(0)) > 0) Then
        OriginalStr = Left(OriginalStr, InStr(OriginalStr, Chr(0)) - 1)
    End If
    StripNulls = OriginalStr
End Function

Function FindFilesAPI(path As String, SearchStr As String, FileCount As Integer, DirCount As Integer)
    'KPD-Team 1999
    'E-Mail: KPDTeam@Allapi.net
    'URL: http://www.allapi.net/

    Dim FileName As String ' Walking filename variable...
    Dim DirName As String ' SubDirectory Name
    Dim dirNames() As String ' Buffer for directory name entries
    Dim nDir As Integer ' Number of directories in this path
    Dim i As Integer ' For-loop counter...
    Dim hSearch As Long ' Search Handle
    Dim WFD As WIN32_FIND_DATA
    Dim Cont As Integer
    If Right(path, 1) <> "\" Then path = path & "\"
    ' Search for subdirectories.
    nDir = 0
    ReDim dirNames(nDir)
    Cont = True
    hSearch = FindFirstFile(path & "*", WFD)
    If hSearch <> INVALID_HANDLE_VALUE Then
        Do While Cont
        irName = StripNulls(WFD.cFileName)
        ' Ignore the current and encompassing directories.
        If (DirName <> "." And (DirName <> ".." Then
            ' Check for directory with bitwise comparison.
            If GetFileAttributes(path & DirName) And FILE_ATTRIBUTE_DIRECTORY Then
                dirNames(nDir) = DirName
                irCount = DirCount + 1
                nDir = nDir + 1
                ReDim Preserve dirNames(nDir)
            End If
        End If
        Cont = FindNextFile(hSearch, WFD) 'Get next subdirectory.
        Loop
        Cont = FindClose(hSearch)
    End If
    ' Walk through this directory and sum file sizes.
    hSearch = FindFirstFile(path & SearchStr, WFD)
    Cont = True
    If hSearch <> INVALID_HANDLE_VALUE Then
        While Cont
            FileName = StripNulls(WFD.cFileName)
            If (FileName <> "." And (FileName <> ".." Then
                FindFilesAPI = FindFilesAPI + (WFD.nFileSizeHigh * MAXDWORD) + WFD.nFileSizeLow
                FileCount = FileCount + 1
                List1.AddItem path & FileName
            End If
            Cont = FindNextFile(hSearch, WFD) ' Get next file
        Wend
        Cont = FindClose(hSearch)
    End If
    ' If there are sub-directories...
    If nDir > 0 Then
        ' Recursively walk into them...
        For i = 0 To nDir - 1
            FindFilesAPI = FindFilesAPI + FindFilesAPI(path & dirNames(i) & "\", SearchStr, FileCount, DirCount)
        Next i
    End If
End Function
Sub Command1_Click()
    Dim SearchPath As String, FindStr As String
    Dim FileSize As Long
    Dim NumFiles As Integer, NumDirs As Integer
    Screen.MousePointer = vbHourglass
    List1.Clear
    SearchPath = Text1.Text
    FindStr = Text2.Text
    FileSize = FindFilesAPI(SearchPath, FindStr, NumFiles, NumDirs)
    Text3.Text = NumFiles & " Files found in " & NumDirs + 1 & " Directories"
    Text4.Text = "Size of files found under " & SearchPath & " = " & Format(FileSize, "#,###,###,##0" & " Bytes"
    Screen.MousePointer = vbDefault
End Sub