Instacam (iOS) app for $0.99

Instacam means "Take retro photo instantly". It is designed for creating square vintage photos and share through Instagram, Facebook and Twitter. With live video preview, your favorite "moment" will never be gone when shooting photos, you can see how a photo with live effects will look like before you decide to shoot. You can also import photos from photo album and apply any live effects by tapping the effects icons.+