A free iPhone app from printer giant Hewlett Packard allows you to wirelessly print your photos.
HP's iPrint Photo, which also works on the iPod Touch, sends a selected photo to an inkjet printer on a Wi-Fi network. It also uses Apple's Bonjour networking technology to help identify HP wireless printers on the network.
Right now, the app only works with JPEG images, and only prints in standard 4×6" size. According to an HP spokeswoman, additional features and functionality will be decided with future versions of the software.
[Available from iTunes]