Emre Safak , Jun 06, 2007; 02:28 p.m.
People who have done it will tell you it is not just about the toning, but the unique tonality. Such difference aside, I find Imagenomic Realgrain to be an asset in emulating all things "film".
Here is a picture (it's puny, but the server's going to complain about the size anyway) to show off the plug-in's capabilities. I know it is not a platinum print, but you get the idea.
Realgrain did the heavy lifting