Receipt printing
Does anyone have a suggestion for a receipt printer that works with AirPrint?
iPad 2 Wi-Fi
I'm not aware of an AirPrint-compatible receipt printer. The Epson Mobilelink P60 series and the Star Micronics T300 will work over wi-fi, but not being AirPrinter printers you'll have to find a third-party printing app that will work, such as PrintCentral. All such apps have limitations, so check them out thoroughly before you pay for any such app.
Regards.