i wrote a tutorial on how to apply textures to photographs, that you can find here.
here are my top 5 places that i find some really awesome textures.
1. Flora Bella Collection - she puts together some of the most beautiful textures. just one set comes with so many different looks that suite an array of styles for your phtoographs. but it's really hard to just buy one set. :)
2. Shadowhouse Creations - jerry has come up with some really dramatic textures. and he is kind enough to have them available for free.
3. Paint the Moon - annie has some beautiful and delicate textures, that i find give my photos a very peaceful look.
4. Regularjane - i just recently found these and so far love what i have used. lots of great bokah.
5. web treats - another new one to me, but have enjoyed looking through all of the work.
and now, for a little texture love...
this one is shot out of camera, of my son playing in the grass
and this one i used an action from paint the moon and a texture from flora bella.