Checking Duplicate Values within a list using SpQuery.

try
            {
                SPWeb curentWeb = SPControl.GetContextWeb(Context);
                SPList lst = curentWeb.Lists["Telno"];
                SPQuery sQuery = new SPQuery();
                sQuery.Query = "<Where><Eq><FieldRef Name='Title' /><Value Type='Text'>" + txtFname.Text.ToString().ToLower() + "</Value></Eq></Where>";
                SPListItemCollection myColl = lst.GetItems(sQuery);
                if (myColl.Count > 0)
                {
                    strError += "<Script Language='JavaScript' type='JavaScript'>";
                    strError += "alert('Friend Name Already Available');";
                    strError += "</Script>";
                }
                else
                {
                    strError += "<Script Language='JavaScript' type='JavaScript'>";
                    strError += "alert('Friend Name Not Available');";
                    strError += "</Script>";
                }
            }
            catch (Exception ex)
            {
                strError += ex.ToString();
            }