how to set the default value in the dropdownlist control

I am trying to show the list of names in the dynamic drop down listbox, using the following code.

 <asp:DropDownList ID="lstLearnItName" runat="server" DataSourceID="dsLearnItNames"
                                    DataTextField="LearnItName" DataValueField="LearnItID">
                                   
                                     
                        <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"
                         ErrorMessage="enter a Product ID" ControlToValidate="lstLearnItName"
                          SetFocusOnError="True" Display="Dynamic"></asp:RequiredFieldValidator>


<asp:SqlDataSource ID="dsLearnItNames" runat="server" ConnectionString="<%$ ConnectionStrings:sConnectionString %>"
                SelectCommand="SELECT * FROM [LearnItName]"></asp:SqlDataSource>


I just wanted to know how I can add a static listitem and set it to the default.

for an instance: <asp:ListItem Selected="true" Text="Please select" Value=""></asp:ListItem>

So that I can force the user to select an item before navigating to the next.

thanks in advance

regards
kay