For some high-level info please see http://www.infoworld.com/t/mobile-technology/surprise-ios-and-android-printing-gotchas-199586
Android does not have a standard print API, and that's why we do not have printing support out of the box.
http://stackoverflow.com/questions/6188067/how-to-print-the-pdf-file-from-wireless-printer
I would suggest Google Cloud Print as a solution (https://developers.google.com/cloud-print/docs/android), since it has some good support for Android.