Как узнать версию своего приложения.

function GetVersion: string;
var
     S : WideString;
     Size : DWORD;
     Buffer : Pointer;
     Ver : ^VS_FIXEDFILEINFO;
     DW : DWORD;
begin
  result := 'x.x.x.x';
  S := GetModuleName(hInstance)+#0;
  Size := GetFileVersionInfoSize(PWideChar(S),DW);
  if Size>0 then
  begin
    GetMem(Buffer,Size);
    if GetFileVersionInfo(PWideChar(S),0,Size,Buffer) then
    begin
      GetMem(Ver,SizeOf(VS_FIXEDFILEINFO));
      VerQueryValue(Buffer,'\',Pointer(Ver),Size);
      result := Trim(IntToStr(Ver.dwFileVersionMS shr 16))+'.'
         + Trim(IntToStr(Ver.dwFileVersionMS and $FFFF))+'.'
         + Trim(IntToStr(Ver.dwFileVersionLS shr 16))
         + Trim(IntToStr(Ver.dwFileVersionLS and $FFFF));
    end;
    FreeMem(Buffer);
  end;
end;

Hint:
Не забудьте включить в настройках проекта "Version Info \ Include version information in project"