DataTable GetSforceData(string strSQL, int iBatchSize)
        {
            DataTable dt = null;
            
            SforceService binding = new SforceService();
            
           
            //get account name, account password and security token here            
            LoginResult lr = binding.login(strAccountName,strAccountPassword + strSecurityToken);

            if (!lr.passwordExpired)
            {
                binding.Url = lr.serverUrl;
                binding.SessionHeaderValue = new partnerWSDL.SessionHeader();
                binding.SessionHeaderValue.sessionId = lr.sessionId;

                partnerWSDL.QueryResult qr = null;
                binding.QueryOptionsValue = new partnerWSDL.QueryOptions();
                binding.QueryOptionsValue.batchSize = iBatchSize;
                binding.QueryOptionsValue.batchSizeSpecified = true;
                try
                {
                    qr = binding.query(strSQL);
                }
                catch (Exception e)
                {
                    MessageBox.Show(e.ToString(), "Error peforming query");
                    return null;
                }

                bool done = false;

                if (qr.size > 0)
                {
                    dt = new DataTable();
                    partnerWSDL.sObject sOtmp = (partnerWSDL.sObject)qr.records[0];
                    
                    for (int i = 0; i < sOtmp.Any.Length; i++)
                    {
                        dt.Columns.Add(sOtmp.Any[i].LocalName);
                    }
                    string[] prValues = new string[sOtmp.Any.Length];
                    while (!done)
                    {
                        for (int i = 0; i < qr.records.Length; i++)
                        {
                            sOtmp = (partnerWSDL.sObject)qr.records[i];
                            for (int j = 0; j < sOtmp.Any.Length; j++)
                            {
                                if (sOtmp.Any[j].ChildNodes.Count > 1)
                                {
                                    prValues.SetValue(sOtmp.Any[j].ChildNodes[2].InnerText, j);
                                }
                                else
                                {
                                    prValues.SetValue(sOtmp.Any[j].InnerText, j);
                                }
                            }

                            dt.Rows.Add(prValues);
                        }

                        if (qr.done)
                        {
                            done = true;
                        }
                        else
                        {
                            qr = binding.queryMore(qr.queryLocator);
                        }
                    }
                }
            }

            return dt;
             
        }

 That code could get you started. It takes a query and returns the results in a datatable