The title is self-explanatory, but I'll show you all what I've done thus
far.

Here's the aspx side of things(trimmed, of course) and javascript:
<form name="form1" id="Form1" method="post" runat="server">
<table width="100%">
<tr>
<td>
<asp:CheckBoxList Runat="server" id="CheckBoxList1">
<asp:ListItem Value="a">Checked a</asp:listitem>
<asp:ListItem Value="b">Checked b</asp:listitem>
<asp:ListItem Value="c">Checked c</asp:listitem>
<asp:ListItem Value="d">Checked d</asp:listitem>
<asp:ListItem Value="e">Checked e</asp:listitem>
</asp:CheckBoxList>
</td>
</tr>
<tr>
<td>
<div><b><i>Action notes</i></b></div>
</td>
</tr>
<tr>
<td>
<textarea id="notes" rows="3" cols="25" runat="server"
NAME="notes"></textarea>
</td>
</tr>
</table>

I tried to stick the javascript below into the page_load event, but it's
just not working. :( Any clues? Am I on the right track? Thanks!

CheckBoxList1.Attributes.Add("onclick", "javascript:form1.notes.value =
'this is a test'")