Print from iPhone 4 to Lexmark printer

There's a list of printers that support AirPrint, the native mechanism for printing from iOS, here:

http://support.apple.com/kb/HT4356

The 7675 does not appear to be one of them. There are third-party apps available that can print to non-AirPrint wireless printers, though all such apps have limitations. You can also route the printing through your computer. If you have a Mac, Printopia might be worth a look:

http://www.ecamm.com/mac/printopia/

Another option for both Windows and Mac systems is Fingerprint. You could also consider an AirPrint-capable print server. Lantronix makes a couple of models, including one that supports a USB printer:

http://www.lantronix.com/it-management/xprintserver/xprintserver-t2.html

Regards.

That printer is not an AirPrint - enabled printer.

You can use the donation-supportedhandyPrint or Ecamm'sPrintopia ($19.95 with free trial) to enable your Mac to act as a print server. The Mac must be "on" but may be asleep for them to work, as long as you enabled "Wake for Network Access" in System Preferences > Energy Saver, enabled Printer Sharing in System Preferences > Sharing, and have the Mac, the iPad, and the printer all on the same wireless network.

Your router must also be compatible with AirPrint and support the Bonjour Sleep Proxy. All Apple AirPort Base Stations do (obviously); third party devices may require a firmware update.

You can also buy this standalone print server:

http://www.lantronix.com/it-management/xprintserver/xprintserver.html

These options enable you to use any printer available to your network, even older ones that may predate AirPrint by decades.

Otherwise you will need to buy an AirPrint printer or multifunction device.

i would also have a look at print n share for printing too