Option Explicit
Private Declare Function InternetOpen Lib "wininet.dll" Alias "InternetOpenA" (ByVal sAgent As String, ByVal lAccessType As Long, ByVal sProxyName As String, ByVal sProxyBypass As String, ByVal lFlags As Long) As Long
Private Declare Function InternetOpenUrl Lib "wininet.dll" Alias "InternetOpenUrlA" (ByVal hInternetSession As Long, ByVal sURL As String, ByVal sHeaders As String, ByVal lHeadersLength As Long, ByVal lFlags As Long, ByVal lContext As Long) As Long
Private Declare Function InternetReadFile Lib "wininet.dll" (ByVal hFile As Long, ByVal sBuffer As String, ByVal lNumBytesToRead As Long, lNumberOfBytesRead As Long) As Integer
Private Declare Function InternetCloseHandle Lib "wininet.dll" (ByVal hInet As Long) As Integer
Private Const IF_FROM_CACHE = &H1000000
Private Const IF_MAKE_PERSISTENT = &H2000000
Private Const IF_NO_CACHE_WRITE = &H4000000
Private Const BUFFER_LEN = 256

Public Function CodigoWeb(Pagina As String) As String
Dim sBuffer As String * BUFFER_LEN, iResult As Integer, sData As String
Dim hInternet As Long, hSession As Long, lReturn As Long
hSession = InternetOpen("vb wininet", 1, vbNullString, vbNullString, 0)
If hSession Then hInternet = InternetOpenUrl(hSession, Pagina, vbNullString, 0, IF_NO_CACHE_WRITE, 0)
If hInternet Then
iResult = InternetReadFile(hInternet, sBuffer, BUFFER_LEN, lReturn)
sData = sBuffer
Do While lReturn <> 0
iResult = InternetReadFile(hInternet, sBuffer, BUFFER_LEN, lReturn)
sData = sData + Mid(sBuffer, 1, lReturn)
Loop
End If
iResult = InternetCloseHandle(hInternet)
CodigoWeb = sData
End Function

Private Sub Form_Load()
MsgBox CodigoWeb("http://www.google.com.ar")
End Sub