[[seoane]]

Prueba con esto:

Código Delphi [-]
function LoadUTF8FromFile(Filename: string): WideString;
var
  Stream: TMemoryStream;
  Size: Integer;
  Str: PWChar;
begin
  Result:= '';
  Stream:= TMemoryStream.Create;
  try
    Stream.LoadFromFile(Filename);
    Size:= MultiByteToWideChar(CP_UTF8,0,Stream.Memory,
      Stream.Size,nil,0);
    if Size > 0 then
    begin
      GetMem(Str,(Size+1)*Sizeof(WideChar));
      FillChar(Str^,(Size+1)*Sizeof(WideChar),#0);
      try
        if MultiByteToWideChar(CP_UTF8,0,Stream.Memory,
           Stream.Size,Str,Size) > 0 then
        begin
          Result:= WideString(Str);
        end;
      finally
        FreeMem(Str);
      end;
    end;
  finally
    Stream.Free;
  end;
end;