public class BottomViewStateModule : IHttpModule
{

    #region IHttpModule Members

    public void Init(HttpApplication context)
    {
        context.BeginRequest += new EventHandler(BeginRequest);
    }

    public void Dispose()
    {
    }

    #endregion

    private void BeginRequest(object sender, EventArgs e)
    {
        HttpApplication Application = sender as HttpApplication;
        String OriginalString = Application.Request.Url.OriginalString;
        if (OriginalString.ToUpperInvariant().Contains(".ASPX"))
        {
            Application.Response.Filter = new ViewStateFilter(Application.Response.Filter);
        }
    }

    private class ViewStateFilter : Stream
    {
        #region Private Fields

        private Stream _originalFilter;
        private String _viewStateInput = String.Empty;
        
        #endregion

        #region Constructors

        public ViewStateFilter(Stream originalFilter)
        {
            _originalFilter = originalFilter;
        }

        #endregion

        #region Public Overrides Properites

        public override bool CanRead { get { return true; } }
        public override bool CanSeek { get { return true; } }
        public override bool CanWrite { get { return true; } }
        public override long Length { get { return 0; } }
        public override long Position { get; set; }

        #endregion

        #region Public Overrides Methods

        public override void Flush()
        {
            _originalFilter.Flush();
        }
        public override int Read(byte[] buffer, int offset, int count)
        {
            return _originalFilter.Read(buffer, offset, count);
        }
        public override long Seek(long offset, SeekOrigin origin)
        {
            return _originalFilter.Seek(offset, origin);
        }
        public override void SetLength(long value)
        {
            _originalFilter.SetLength(value);
        }
        public override void Close()
        {
            _originalFilter.Close();
        }
        public override void Write(byte[] buffer, int offset, int count)
        {
            Byte[] data = new Byte[count];
            Buffer.BlockCopy(buffer, offset, data, 0, count);
            String html = Encoding.Default.GetString(buffer);

            html = MoveViewState(html);

            Byte[] outdata = Encoding.Default.GetBytes(html);
            _originalFilter.Write(outdata, 0, outdata.GetLength(0));
        }

        #endregion

        #region Private Methods

        private String MoveViewState(String html)
        {
            String viewStateLine = "<input type=\"hidden\" name=\"__VIEWSTATE\"";
            Int32 startPoint = 0;
            Int32 endPoint = 0;

            if (String.IsNullOrEmpty(_viewStateInput))
            {
                startPoint = html.IndexOf(viewStateLine);
                if (startPoint >= 0)
                {
                    endPoint = html.IndexOf("/>", startPoint) + 2;
                    Int32 viewstateLength = endPoint - startPoint;
                    _viewStateInput = html.Substring(startPoint, viewstateLength);

                    html = html.Remove(startPoint, viewstateLength);
                }
            }

            int formEndStart = html.IndexOf("</form>") - 1;
            if (formEndStart >= 0)
            {
                html = html.Insert(formEndStart, _viewStateInput);
            }

            return html;
        }

        #endregion
    }
}

<httpModules>
    <add type="BottomViewStateModule" name="BottomViewStateModule"/>
</httpModules>