这是在一个线程中封装sakemail的代码，是iCompanion源码的一部分
虽然只使了一个线程，功能也相当简单，但原理基本就是这样了
在大范围的使用中工作相当稳定。

const
     WM_SHOWNOTIFY = WM_USER + 100;

type
  TMailChkThread = class(TThread)
     protected
          procedure execute;override;
     public
          MailChk:TMailCheck;
          SakPOP:TSakPOP;
          MailIndex:integer;
          MailChkInfo:string;
          MailNumber:integer;
          
          constructor Create(MailChkObj:TMailCheck);
          destructor Destroy;override;
          procedure RefMailInfo;
  end;

constructor TMailChkThread.Create(MailChkObj:TMailCheck);
begin
     Inherited Create(True);
     SakPOP := TSakPOP.Create(nil);
     MailChk := MailChkObj; 
end;

destructor TMailChkThread.Destroy;
begin
     SakPOP.free;
     SakPOP := nil;
     inherited Destroy;
end;

procedure TMailChkThread.execute;
var
   i,j:integer;
   PassInput:string;
   MailCount,LoginCount:integer;
begin
     MailCount := 0;
     LoginCount := 0;

     for i := 0 to MailCheck.count -1  do  // MailCheck是一个自定义，封装了对邮箱数据的访问
     with MailChk.Items[i] do 
     begin
        MailIndex := i;
        if Enabled = false then Continue;
        if Pass = '' then
        begin
             if NOT CInputQuery ('网络伴侣 - 请输入密码', '服务器：'+Server+ #13#10 +'用户名：'+ Login+ #13#10 +'密码：' , PassInput,true) then break
             //CInputQuery 是一个自定义函数，显示输入窗体以取得输入的字符串
             else Pass := PassInput;
        end;

        SakPOP.Host := Server;
        SakPOP.Port := '110';
        SakPOP.UserId := Login;
        SakPOP.UserPasswd := Pass;

        try
              SakPOP.Connect;
              if SakPOP.POPError then
              begin
                 MailNumber := 0;
                 MailChkInfo := '无效的服务器';
                 Synchronize(RefMailInfo);
                 Continue;
              end;

              Application.ProcessMessages;
              if Terminated then Break;

              if not SakPOP.login then
              begin
                 MailNumber := 0;
                 MailChkInfo := '无效的用户名或密码';
                 Synchronize(RefMailInfo);
                 Continue;
              end;

              Application.ProcessMessages;
              if Terminated then Break;

              SakPOP.Init;
              MailNumber := SakPOP.MsgsCount;
              MailChkInfo := '完成';
              Synchronize(RefMailInfo);
              if SakPOP.MsgsCount > 0 then
              begin
                inc(LoginCount);
                inc(MailCount,SakPOP.MsgsCount);
              end;
              SakPOP.Quit;
        except
           MailNumber := 0;
           MailChkInfo := '网络错误';
           Synchronize(RefMailInfo);
           break;
        end;

        Application.ProcessMessages;
        if Terminated then Break;

     end;

     if MailCount > 0 then
     begin
          PostMessage(frmBody.Handle,WM_SHOWNOTIFY,LoginCount, MailCount);  
          //全部检测完成，向主窗体发送消息，主窗体做相应反应
     end;
end;

procedure TMailChkThread.RefMailInfo; //更新listview
var
   ListItem: TListItem;
begin
     begin
        ListItem := frmbody.LVMail.Items.Add;
        ListItem.ImageIndex := 3;
        ListItem.Caption := MailChk.Items[MailIndex].Name;
        ListItem.SubItems.Add(inttostr(MailNumber));
        ListItem.SubItems.Add(MailChkInfo);
     end;

end;

procedure TfrmBody.btnChkMailClick(Sender: TObject);  //启动检测邮件线程
var
   dwExitCode:DWORD;
   ThreadID:DWORD;
begin
     if OnlineFlag = false then
     begin
        msgbox('在离线状态下不能检测邮件，请拨号上网。','提醒',MB_OK+MB_ICONINFORMATION);
        exit;
     end;

     if ThreadMail <> nil then  //取消按钮被按下
     begin
        ThreadMail.Terminate;
        exit;
     end;

     btnChkMail.Caption := '取消';
     LVMail.Items.Clear;

     ThreadMail := TMailChkThread.Create(MailCheck);
     ThreadMail.OnTerminate := frmbody.onMailTerminated;
     hThread := ThreadMail.Handle;
     ThreadMail.Resume;

end;

procedure TfrmBody.WMShowNofity(var Message: TMessage);
begin

     ShowNotifyForm('在' + inttostr(Message.WParam) + '个信箱检测到' + inttostr(Message.LParam) + '封信件！');

end;

procedure TfrmBody.FormDestroy(Sender: TObject);
var
   i:integer;
   dwExitCode:DWORD;
begin
     //很重要的一步，在程序退出时如果线程仍在运行，必须强行杀死该线程
     if ThreadMail <> nil then
     begin
        ThreadMail.Suspend;
        CloseHandle(ThreadMail.Handle);
     end;

end;

其他大虾有例子，也请拿出来交流交流。