In case you don't have an airprint compatible printer to call your own but still want the ability to print directly (PDF,JPG,Word, Excel and Web pages) from your iPhone, get
printer pro which is available for free today from the App store as part of the App of the Day feature.
You'll have to install a
helper program on your PC or Mac first though for this to work and the iphone from which you want to print needs to be on the same network as the printer that is connected to the PC which has the printer pro helper program installed.
