<%
set conn=Server.CreateObject("ADODB.Connection")
conn.Provider="Microsoft.Jet.OLEDB.4.0"
conn.Open(Server.Mappath("northwind.mdb"))
set rs=Server.CreateObject("ADODB.recordset")
sql="SELECT * FROM Customers"
rs.Open sql,conn
if rs.Supports(adApproxPosition)=true then
i=rs.RecordCount
response.write("The number of records is: " & i)
end if
rs.Close
conn.Close
%>

tu trouveras la doc ADO ici
http://www.w3schools.com/ado/ado_ref_recordset.asp
ou ici
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ado270/htm/mdobjodbrec.asp