SharePoint - insert data from dropdownlist to lists inside the NewForm.aspx

i modified NewForm.aspx of Sharepoint 2007, and i added a dropdownlist. How can i save the item in the dropdowlist going to a column in the lists. In other words I want to replace SharePoint FormField Age, and replace it with a dropdown

here's a portion of the code that i have.
<td width="400px" valign="top" class="ms-formbody">
     <asp:DropDownList runat="server" id="ddlAge" DataValueField="Age" DataTextField="Age"  DataSourceID="RetrieveAgePass">
     </asp:DropDownList>
     <SharePoint:FormField runat="server" id="ff8{$Pos}" ControlMode="New" FieldName="Age" __designer:bind="{ddwrt:DataBind('i',concat('ff8',$Pos),'Value','ValueChanged','ID',ddwrt:EscapeDelims(string(@ID)),'@Age')}"/>
     <SharePoint:FieldDescription runat="server" id="ff8description{$Pos}" FieldName="Age" ControlMode="New"/>
 </td>