Epson has released an iPhone app that allows photo printing via a Wi-Fi connection. Epson iPrint lets you send photos stored on your phone to any network-capable Epson printer (including a number of printers in the Artisan, Stylus, and WorkForce lines).
The app's automatic printer discovery feature identifies printers available on your network, and no computer is needed to make the printing magic happen.
You have a few limited print options: in addition to standard printing on plain paper, you can produce borderless prints on fancy photo paper or choose from a number of paper sizes (4-by-6, 5-by-7, letter size, and A4). Of course, if you're printing photos taken with the iPhone camera (even the one on the 3G S), be prepared for mediocre quality - iPhone pictures really aren't meant to be framed.
Epson is the third to join the iPhone printing game. HP released its own app - called HP iPrint Photo - at the beginning of 2009 and updated it in November and Canon also released its Canon Easy-PhotoPrint for iPhone this autumn.
Epson's app works on any iPhone or iPod Touch running iPhone OS 2.2.1 or later and is available for free in Apple's App Store.