From Ignacio Vina:
Camera illusion is a camera application that lets you process photos in real-time, previewing and taking amazing pictures combining filters, effects and masks. Additional functionality for iPhone 4: Use front camera for fun photos; Enable LED flash/torch to light the pictures better. Features: 17 filters: mono, negative, sepia, aqua, old photo, pencil, chalk, emboss, lomo, thermal, comic, x-ray, oil, black and white, red channel, green channel and blue channel. + 12 effects: thin, fat, tall, short, horizontal/vertical mirror, pixelization, fisheye, mosaic, light tunnel, pinch and twirl. + 8 masks: frame, wanted poster, garden sign, monitor, bricks, cork board, menu board and negative.