O'Print (AirPrint Activator for Windows)

[Zero3K]

Here's the description of it from its listing on Softpedia:

O'Print is a handy and reliable application designed to deliver a simple method from printing files from an iPad or an iPhone device. It manages to do so by activating the AirPrint feature for all of your installed printers. In addition, you can also password protect each printer for an enhanced level of security.

(BTW, it can also print from devices running MAC OS X)

Homepage - http://www.oprintware.com/
Screenshots - http://www.softpedia.com/progScreenshots/O-Print-Screenshot-240525.html
Download - http://oprintware.com/update/oprinttrial.zip
License - Shareware (30 Day Trial)
Size - 7.45 MB