You've got a few options to create that kind of effect.
Firstly you could overlay textures onto your image. Either download them (from somewhere like mayang.com/textures/) or make them from your own photography or scans. Try different blending modes (overlay, soft light, hard light) and opacities, and play with running the high-pass filter on them.
Secondly is custom brushes. Download some (deviantart.com has lots of that kind of brush) or make your own. Then get to work brushing in dust and scratch texture. The most time consuming method, but the most controlled.
Or lastly you could play around with a plug-in. I've never personally used one to create this kind of effect. You could try downloading om130nd.exe from www.boxtopsoft.com/plugpage/
Like I said, no idea what its like. I think DigiEffects have a similar thing in their Aurorix plugin package.
Hope this helps.