This tutorial will show you one idea about how you can make your photo look old. As always, start with new image, fill background with solid color.
Apply a bit of Noise effect (Effects - Noise - Add Noise), about 3-4%
Fade effect, so that amount of noise is reduced (Ctrl-Shift-F).
Add a bit of Sponge effect (menu Effects - Artistic - Sponge). Tweak effect settings to your liking. After effect is applied, use Fade (Ctrl-Shift-F) again to make Sponge less visible, and let a bit of Noise come through.
I found this nice old paper image in stock photos - you can also scan it if you have it. Paste image in your document, then desaturate (Ctrl-Shift-U).
Set layer blend mode to Overlay, adjust opacity as needed (i set it about 30-40%). Now our old paper is ready, lets put a photo in it!
Here is the original photo that I took in my travel to Venice.Paste it into our document...
..and then simply change its layer blend mode to Overlay! That is all!
If you want to make image darker, duplicate layer with photo and change its blend mode to Multiply and set opacity to 40-60%.