If light leak effects are your cup of tea, you may want to check out the Windows Phone 8 photography app Lights of Cali.
The app has over 230 light leak effects, a wide assortment of text overlays and the ability to add your signature to your photos. You can apply these effects to existing images or launch a camera app to capture new images to edit. Lights of Cali also has a social network where you can share your creations and view other member's use of light leaks.
In just tinkering with Lights of Cali over the past few days, it comes across as a capable photography app for your Windows Phone.