WebClient webClient = new WebClient();
Stream stream = webClient.OpenRead("http://forum.antichat.ru");
StreamReader streamReader = new StreamReader(stream);
string html = streamReader.ReadToEnd();
Regex reg = new Regex(@"(<a href=.*>.+</a>)");
MatchCollection mc = reg.Matches(html);
string links = "";
foreach (Match match in mc) {
     links += match.Value + "<br/>";
}
Label1.Text = links;