I use Dave Marsit's action (the one linked above) and it does a great job. I've posted about this before, but there is another app that is free for personal use (the trial never expires) that has camera profiles as well, if you want to pay for it, it will plug in to photoshop and that is neatimage
www.neatimage.com it does a very nice job. However, what I use most these days, is Fred Mirandas ISOxPro Plug in, it's only 20 bucks and does an excellent joband it's a little faster on a 35mb file than either of the other two above.