Adobe Software may never port Photoshop over to an iPhone app, but Nevercenter has done the next best thing: a photo-tweaking app that'll make your camera-phone snapshots stand out from the crowd.
CameraBag is a collection of filters that quickly and creatively change the look of your iPhone snapshots (similar to how a Photoshop plug-in can, say, smooth a model's skin or emulate your favorite film stock). There are seven presets that can instantly change your image to vibrant, jazzy colors, understated black and white, and quite a few things in-between. You can scroll through the presets to compare their looks and save the processed picture you like the most. Want more control? An options panel is available for camera behavior, image size, cropping and border effects, etc.
Become the next Richard Avedon! (Or the next Larry Flynt. Your choice.)
CameraBag v1.2.1 originally listed for a very reasonable US$4.99, but is currently on sale for only US$2.99; for anyone who wants to give their "iPhotos" some added oomph, that's a steal. (As we went to press, CameraBag v1.3 is on the verge of release, with a new fisheye-lens effect; it will be available as a free upgrade to current owners.)
[Available exclusively through iTunes]
Accessories & Apps: Beta Testers Wanted
iOS Firmware/IPSW Download Guide
Legacy iTunes Download Archive
App Store Top Charts
iPhone and Android Resale Value Charts
USA iPhone Carrier Plans Compared
Complete iPhone Jailbreaking Guide 
Complete iPhone Specification Matrix 
You can try another application: Model Pose for iPhone, it a useful handbook and toolbox for photographer. The poses are useful, I really love it. This application does have a lot of line drawings divided up into groups to search for the pose that fits your situation.
you can find it in iTunes App Store:
http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=295449605&mt=8