How to add Default Item To Dropdown List in asp.net

Hi All,
I want to add empty or "select" as string in dropdown list.
But when i do something like below;
<asp:ListItem Selected="True"></asp:ListItem> Then after doing databind with the dataset  to dropdown list. It disappears.
Also after inserting the value as listitem i get same thing.
It doesnt appears in the drop down list.
I want to do something like below.
My Id for dropdown list as = ddl1
Then afterwards,
ListItem li = new ListItem();li.Selected = true;li.Text = "Select";li.Value = "0"
Then 
ddl1.Items.add(li);
It doesnt work.
Please provide solution for this problem.
Regards,
Jayesh(From India,Mumbai)