RTLabel *someLabel = [[RTLabel alloc] init];
someLabel.frame = CGRectMake(0.f,0.f,300.f,100.f);
someLabel.text = @"<p>Some <b>HTML</b></p>";
CGSize optimumSize = [someLabel optimumSize];
someLabel.frame = CGRectMake(0.f,optimumSize.height);