In case you haven't noticed, I'm a huge fan of iPhone photography apps. I've written about Best Camera, played with ColorSplash, and taken panoramic photos with Pano. When I noticed the $1.99US Lo-Mob [iTunes Link] while doing my weekly pass through the photo apps, I decided to buy it and give it a try.

Part of my fascination with iPhone photo apps is that the flexibility of the software combines with the camera that is always at your fingertips, and you can do things with your photos with a few taps that would have taken hours in a darkroom. Lo-Mob provides 33 different effects that give your iPhone pics the look of taking photos with old film, instant film, 35 mm film in a medium-format camera, and more. With many of the effects, changes with saturation, focus, and tint are mixed with artifacts (dust on the frame, for example), vignetting, and frames.

As soon as you either take a new photo or select an existing one in Lo-Mob, the app takes about 10 - 12 seconds to pre-process all of the images. The result is that when you go to choose your effect, you see exactly how it's going to look in a small thumbnail image located next to information about the effect. After you've selected your effect, you see a full size image that can then be saved in the original photo resolution and then shared with others through email, Facebook, or Twitter.

Now for some fun! We have three Lo-Mob promo codes to give away to three lucky TUAW readers. Here's the scoop:

• Open to legal US residents of the 50 United States and the District of Columbia who are 18 and older.
• To enter leave a comment telling us what you would take a photo of and then "retro-ize" with Lo-Mob.
• The comment must be left before Wednesday, December 16, 2009, 11:59PM Eastern Standard Time.
• You may enter only once.
• Three winners will be selected in a random drawing.
• Prizes: Promo Code for one copy of Lo-Mob (Value: US$1.99)
• Click Here for complete Official Rules.

Check out the gallery below for an idea of some of the cool effects you can slap on those iPhone photos.