Update: as of the last few versions, the standard HP firmware updater appears to be working fine on the most recent OS X versions. What follows is now strictly of academic value.
I have had an HP P1102w printer for over a year now.
I've had no complaints about it so far, but a firmware update was recently released that adds AirPrint support, allowing printing from iOS devices.
The problem is: the firmware updater refuses to do anything on OS X (at least in 10.6.8 and 10.7.x).
I searched but was never able to find a solution that worked.
So, I did what any normal person would do: I loaded it up in gdb.