How to Print From Your iPhone 4
With the highly anticipated release of Apple's iOS 4.3 operating system came a wide variety of extra features, including AirPrint. AirPrint lets you print emails, photos, Web pages and PDF documents directly from your iPhone via wireless connection with iBooks, Mail, Photos and Safari. If you're not sure if your printer uses a wireless connection, Apple provides a list of AirPrint compatible printers on its website.
Turn on your iPhone and disable the pass code if you use one. Tap either "Mail," "iBooks," "Photos" or "Safari" to open.
Locate the item you want to print. AirPrint is only compatible with iBooks, Mail, Photos and Safari and will not be an available feature in other apps.
Tap the item you want to print, and then tap the "Share" button which resembles a rectangle with an arrow. Tap the "Print" button from the popup menu.
Tap "Select Printer" to select your printer. Verify that the wireless connection for your printer is turned on if AirPrint is unable to find it.
Use the "+" and "-" buttons to select the number of copies you want, then tap the "Print" button.