Hi Sathyaish,

It is definitely possible to use our SOAP API with vb6.  It is not as pretty as .Net, but reliable none the less.  What you need to have a thorough understanding of is SOAP and SOAP namespaces, and one of the MS http/soap libraries.  You can choose from wininet, MSXML or MSSOAP.  Wininet will require that you write a lot of code to parse the inbound and outbound xml and properly setup http header information.  MSSOAP wraps alot of that functionality for you, but may not allow the granularity of control required to properly create and process the messages.  MSXML seems to be the most flexible and popular choice.

In addition you can try pocketSOAP, but I don't think it's mature enough to interop with our service.  pocketSOAP is very promising, but at this stage, it may be more trouble than it's worth.

Below is a snippet that shows how to login.

Option Explicit
Const NAME_SPACES = "xmlns:soapenv=""http://schemas.xmlsoap.org/soap/envelope/"" " & _
                    "xmlns:xsd=""http://www.w3.org/2001/XMLSchema"" " & _
                    "xmlns:xsi=""http://www.w3.org/2001/XMLSchema-instance"" " & _
                    "xmlns:sfdc=""urn:enterprise.soap.sforce.com"""
Private top_g_serverAddress As String '= "https://www.salesforce.com/services/Soap/c/2.0"
Public parseIndex

Public Function initXMLHTTP()
    '//this sucks, but the doc's say that the object has to be reset before it can be reused, just not
    '//how to reset them
    If Not g_xmlhttp Is Nothing Then Set g_xmlhttp = Nothing
    Set g_xmlhttp = New MSXML2.XMLHTTP30
    g_xmlhttp.Open "POST", top_g_serverAddress, False
    g_xmlhttp.setRequestHeader "SOAPAction", """"""
    g_xmlhttp.responseXML.validateOnParse = False
End Function

Public Function doLogin(ByVal userName As String, ByVal password As String)
    Dim s As String
    s = buildLoginQuery(userName, password)
    '//internal callback function from msxml handler
    Dim doc As MSXML2.DOMDocument30
    Set doc = sendRequest(s)

    Do While g_xmlhttp.readyState <> 4
        DoEvents
    Loop
   
    doc.setProperty "SelectionNamespaces", "xmlns=""urn:enterprise.soap.sforce.com"" xmlns:soapenv=""http://schemas.xmlsoap.org/soap/envelope/"""
    Dim nl As IXMLDOMElement
 
    Set nl = doc.selectSingleNode("/soapenv:Envelope/soapenv:Body/soapenv:Fault")
    If nl Is Nothing Then
        loginFinished doc
    Else
        MsgBox nl.selectSingleNode("detail").Text, vbOKOnly + vbCritical, "Error on Login"
    End If
   
End Function

Public Function loginFinished(responseXML)
        Dim resultXML As MSXML2.IXMLDOMElement
        Set resultXML = responseXML.selectSingleNode("/soapenv:Envelope/soapenv:Body/loginResponse/result")

        If resultXML Is Nothing Then
            Debug.Print "Session has no result, possible bad query."
            Exit Function
        End If

        If getResultNodeValue("serverUrl", resultXML) <> "" Then
            URL = getResultNodeValue("serverUrl", resultXML)
        End If
        gblstrSessionID = getResultNodeValue("sessionId", resultXML)
        gblstrUserID = getResultNodeValue("userId", resultXML)
End Function