I use this last solution to print on my Polaroid PoGo printer. If your need is to print wirelessly but without relying on a preexistent network what you will need is a Bluetooth printer, but in that case you will need to jailbreak your iDevice and install the commercial application Celeste from the Cydia store. The AirPrint enabled wireless printer DO NOT offer and Access Point functionality so you can not connect to them if there is not a WiFi network already in place. In fact the are many wireless printers but not all of them implement the AirPrint protocol. The AirPrint is a protocol that make the iOS device NOT to need a driver to print over WiFi.

Any AirPrint enabled wireless printer you need to be connected to a WiFi network, the same to which your iDevice (iPhone or iPad) is connected.