Hi all... As you know I spend a great part of my day organizing and retouching photos of homes which will be printed in my company's monthy real estate magazine. The majority of pictures are taken by our staff using a Nikon Coolpix 8400, very high quality, high resolution photos requiring just some minor cropping or shadow adjustment in Photoshop. But I also get some photos from various other sources, which are very low resolution and very small file size. To make them usable, I have to resample them from 72 dpi up to the 300 dpi required by our printers. The results are typically pretty bad, garbage in - garbage out.
But I just got a Photoshop plugin called Genuine Fractals 4.1 which I'm using just for this very specific task. While you can't make a silk purse from a sow's ear, the results are MUCH better than going through PS's ImageSize dialog. I can actually get something usable for high resolution magazine print using this software.
It's also great for taking a good quality photo and enlarging it to a much greater printing size, even poster size in some cases.
The company is OnOne Software and they have a 30 day trial, which lets you play with it for a while. http://www.ononesoftware.com