I haven't checked the actual web-site as I don't use Photoshop, but I love the effect and can see me using this myself. Where I pinned it from said "How to Create a "Double Exposure" in Photoshop — Daily Epiphanie"
Photoshop tutorials, tips and news The site is fully on auto-pilot and updates all by itself at the time interval you specify. All the best tutorials, tips and lessons! Photoshop is a hugely popular software receiving over 50 million searches/month!
use one tool in photoshop - Curves to lighten up your images, but it can make your colors and contrast pop by making an S curve. To do that, just add a second point in the curves window, and drag it down a bit.
Awesome tutorial on making your photos soft & vintage looking. How to add a "Soft Light" to your photos using Photoshop & the shortcut to easily "Mass Editing" photos with the same effect. Photoshop tips.