JG3D

Photoshop.com has made this iPhone app available via the itunes store for free. Features include: Basics: Crop, Rotate, and Flip Color: Exposure, Saturation, Tint, Black and White Filters: Sketch, Soft Focus Effects: Vibrant, Pop, Border, Vignette Blur, Warm Vintage, White Glow, etc. via gizmodo and 9to5mac

Often, when working in the 3D visualization field one has to composite 3D renderings on top of a photographic background, using Adobe Photoshop. Here is a great tutorial I found on how to do it properly: link