主要是应用 .Net 的 WebRequest ,HttpWebRequest ,WebResponse , HttpWebResponse 几个类.
个人心得: 登录邮箱各不同,分析路径要耐心。 Http 的间断链接，需要把 HttpHeader 获得后再发回去. 压缩包中有个例子(含源码)。
有兴趣的继续研究的朋友可以Mail我 Dev.guyan # Gmail.com 非诚勿扰
private string GetRequestHtml(string URL, Encoding EnCodeing,ReqMethod RMethod)
{
string html = string.Empty;
try
{
req = (HttpWebRequest)WebRequest.Create(URL);
req.AllowAutoRedirect = true;
req.CookieContainer = cookieCon;
req.Credentials = CredentialCache.DefaultCredentials;
req.Method = RMethod.ToString();
req.ContentType = "application/x-www-form-urlencoded";
req.UserAgent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; GTB5; Mozilla/4.0(Compatible Mozilla/4.0(Compatible-EmbeddedWB 14.59 http://bsalsa.com/ EmbeddedWB- 14.59 from: http://bsalsa.com/ ; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; InfoPath.2; .NET CLR 3.5.30729; .NET CLR 3.0.30618; CIBA)";

res = (HttpWebResponse)req.GetResponse();

if (cookieheader.Equals(string.Empty))
{
cookieheader = req.CookieContainer.GetCookieHeader(new Uri(URL));
}
else
{
req.CookieContainer.SetCookies(new Uri(URL), cookieheader);
}

html= new StreamReader(res.GetResponseStream(), EnCodeing).ReadToEnd();
}
catch (Exception ex)
{
html = ex.Message;
}
return html;
}

http://blog.csdn.net/skylen/archive/2009/03/27/4028906.aspx