I upgraded my MVC Application using MSChart to MVC 2 and have ended up with broken image links for the charts.
See my blog entry here:  http://blog.adronbhall.com/post/2010/04/12/MVC-2-Breaks-my-Charts.aspx
I get no build errors anymore, and have completed the following steps.
First, I setup the following web.config lines.
add tagPrefix="asp" namespace="System.Web.UI.DataVisualization.Charting" 
assembly="System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, 
PublicKeyToken=31bf3856ad364e35"
and 
add path="ChartImg.axd" verb="GET,HEAD" 
type="System.Web.UI.DataVisualization.Charting.ChartHttpHandler, 
System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, 
PublicKeyToken=31bf3856ad364e35" validate="false"
(NOTE:  I took the chevrons off so the lines would appear)
The next thing I did was create this page with the following code.  Which should, according to it working in MVC<1, showed 4 charts.
<%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" 
    Inherits="System.Web.Mvc.ViewPage" %>
<%@ Import Namespace="Scorecard.Views" %>
<asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">
    Scorecard
</asp:Content>
<asp:Content ID="applicationTitle" ContentPlaceHolderID="ContentPlaceHolderApplicationName" runat="server">
    <%=Html.Encode(ViewData["ApplicationTitle"])%>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
<form id="form1" runat="server">
<h2>
    Web Analysis Scorecard
</h2>
<table>
    <tr>
        <td>
            <%
                ChartHelper chartHelper = new ChartHelper("Top Countries",
                                                          (double[])ViewData["TopCountryCounts"],
                                                          (string[])ViewData["TopCountries"],
                                                        SeriesChartType.Pie);
                Chart chartPieTwo = chartHelper.ResultingChart;
                // Explode data point with label "USA"
                chartPieTwo.Series["DefaultSeries"].Points[3]["Exploded"] = "true";
                chartHelper.RenderChart(this);
            %>
        </td>
        <td>
            <%
                chartHelper = new ChartHelper("View Cart Trend",
                                              (double[])ViewData["LineValues"],
                                              (string[])ViewData["TopEngines"],
                                              SeriesChartType.Line);
                chartHelper.RenderChart(this);
            %>
        </td>
    </tr>
    <tr>
        <td>
            <%  chartHelper = new ChartHelper("Yesterday's Page Views",
                          (double[])ViewData["ColumnStats"],
                          (string[])ViewData["ColumnStatHeaders"],
                          SeriesChartType.Column);
                chartHelper.RenderChart(this);
            %>
        </td>
        <td>
            <%
                double[] theValues = (double[])ViewData["ColumnStats"];
                double[] newValues = new double[] { 0, 0, 0, 0 };
                int count = 0;
                int daysInMonth = DateTime.DaysInMonth(DateTime.Now.Year, DateTime.Now.Month);
                foreach (double d in theValues)
                {
                    newValues[count] += d * daysInMonth;
                    count++;
                }
                chartHelper = new ChartHelper("Current Month Page Views",
                                              newValues,
                                              (string[])ViewData["ColumnStatHeaders"],
                                              SeriesChartType.Bar);
                chartHelper.RenderChart(this);
            %>
        </td>
    </tr>
</table>
</form>