I've posted before about how much I really love using these digital textures in my photos. There are so many options you can use in Photoshop (or any editing program that allows the blending of multiple layers of work). I find a lot of my free resources on Flickr. If you're familiar with how Flickr works, you can search its Groups for "textures" and find some examples. Just make sure they are marked as free to use in your work. All of the examples here were made using those free texture resources except where noted. (you will need to have some knowledge of Photoshop layers to use the textures, but the links I provided below do give tips on this.)
Joy St. Claire, an extremely talented photographer from Ohio and great lady! you can see the textures she offers on her blog sidebar.) I like the way it came out!
I'm really still learning all of this, so I appreciate any feedback or tips anyone reading may have to share, too. I'll try to include them in a future post because I plan on playing around more with textures. I also have my own textures to offer you, which are free, mostly bokeh textures with circles of blur and light that add a magical, dreamy touch to photos. You can find them at the top of my blog, underneath the header on the Textures link.
Joy St. Claire textures, Moderne, Maggie texture sets
Grunge textures gallery
Textures for Layers - group in Flickr
Florabella's fine art textures set