as my comments suggested, here is solution:
<table class="budgetList">
<thead>
<tr>
<td>Project Number</td>
<td>Account</td>
<td>Project Name</td>
<td>July</td>
</tr>
</thead>
<tbody>
<asp:ListView ID="leaveListView" runat="server" ItemPlaceholderID="itemPlaceholder">
<LayoutTemplate>
<asp:PlaceHolder ID="itemPlaceholder" runat="server" />
</LayoutTemplate>
<ItemTemplate>
<tr class="<%# Container.DataItemIndex % 2 == 0 ? "" : "even" %>">
<td><%# Eval("Project") %></td>
<td><%# Eval("Account") %></td>
<td><%# Eval("ProjectNumber") %></td>
<td><%# Eval("July") %></td>
</tr>
</ItemTemplate>
</asp:ListView>
</tbody>
<tfoot>
<tr class="projectRowTotal">
<td>Project Totals</td>
<td></td>
<td></td>
<td><asp:Label ID="july" runat="server" Text=""></asp:Label></td>
</tr>
</tfoot>
</table>
havent't actually tried it, but should work fine ... + in code, where you bind data:
leaveListView.ItemsSource = <data>;
// simply place the value in label directly
july.Text = <data.sum>
now just make sum in code and you're done, no need for itemdatabound event