I recently discovered the iPhone app called VintageCam and it is amazing. I was browsing the top 25 free apps and since I have about 239039 camera apps already, I decided to try it out and it is gorgeous. You take a picture, and it has a sort of vintagy camera background, and after you've taken a photo, you can change the effects and there are some lovely ones on it, too. My favourites are Neptune, Dark Knight and Crème-Brulée. In total there are 15 effects.
A few snaps I took earlier:
Neptune
Dark Knight
Rainbow
What are your favourite camera apps? I love trying them all out!