First, download AirPrint Activator 2.0 on your Hackintosh or Mac. It will download as a zip file; unzip the file. A folder named "AirPrintActivator" will appear. Run the Air Print Activator app inside (unlike most Mac apps, you don't have to move the app into the Applications folder).
In Air Print Activator, change the off-on switch to "on". Your printer should show up in the box on the right. If it doesn't, go to the Print & Scan section in your Mac's System Preferences, find your printer, and check "Share this printer on the network".
And that's all there is to it! Now you can use AirPrint to print documents, images, and webpages from any supported app on your iPhone, iPod Touch, or iPad.
NOTE: I can't guarantee that AirPrinter Activator will work perfectly. For example, on my Xerox Phaser 6180N laser printer, AirPrint can only print when I use the secondary paper tray (which is usually used for oversize paper). Overall, AirPrint should be functional, but don't expect flawless compatibility.