I had a play and managed to work a way to get what I wanted. Thanks for point
in the right direction. In order to do it I had tackled it as follows;

1> Placed a literal control in the datalist itemtemplate.

2.> edited ItemDataBoundEvent as follows

Protected Sub dlstICEModels_ItemDataBound(ByVal sender As Object, ByVal e As
System.Web.UI.WebControls.DataListItemEventArgs) Handles
dlstICEModels.ItemDataBound

      Dim tmpDataListItem As DataListItem
      tmpDataListItem = CType(e.Item, DataListItem)

       Dim tmpLiteral As Literal
       tmpLiteral = CType(e.Item.FindControl("Literal1"), Literal)
       tmpLiteral.Text = "<img src='UI/images/p.gif' onclick='javascript:"
& tmpDataListItem.ClientID & "_txtQTY.value = (" & tmpDataListItem.ClientID &
"_txtQTY.value * 1) + 1 ;' />"

End Sub

3.> Was suprised that I managed to get it working :).  Key thing to watch
out for is also make sure that you use the correct CASE as javascript is not
as forgiving as VB.net.

Thanks

Neil