Apple is inching closer to releasing 10.6.5. They have released Build 10H574 to developers. This is the fifth seed in two weeks. Don’t expect iOS 4.2 to be released until 10.6.5 is released to the general public, since AirPrint is not supported under 10.6.4.
Maybe one of these days we will actually receive 10.6.5 from Apple. There have been reports that Apple has released 10.6.5 internally, so I’m not sure what is up with this new release mere days after the last one.