Validation On DropDownList Box

I have a dropdownlist (cboViewAlbums) which has displays album values. The first item is a select an album. I am trying to use validation which when lb_create_album linkButton is clicked throws an error if the cboViewAlbums list has the value 0 selected. Below is the code for the this and my attempt:

<asp:DropDownList ID="cboViewAlbums" runat="server"
DataSourceID="SqlDataSource1" DataTextField="album_name"
DataValueField="album_id" Width="250px" AutoPostBack="True" AppendDataBoundItems="true">
<asp:ListItem Value="0">Please select an album...</asp:ListItem>
</asp:DropDownList>
<asp:LinkButton ID="lb_create_album" runat="server">Create Album</asp:LinkButton>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:fpaConnectionString %>"
SelectCommand="SELECT [album_id], [album_name] FROM [fpa_albums] ORDER BY [album_name]">
</asp:SqlDataSource>
<br />
<asp:HyperLink CssClass="example7" ID="hLinkUploadPhotos" NavigateUrl="multiple_upload.aspx" runat="server">Upload Multiple Photos</asp:HyperLink>
<br />
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"
ControlToValidate="cboViewAlbums" ErrorMessage="Please Select an Album"
InitialValue="Please select an album..."></asp:RequiredFieldValidator>