I've written about printer support elsewhere in the series (http://www.onlamp.com/pub/ct/15). While the general impression is that Linux printing differs from BSD printing, there's not really that much difference. Both use ghostscript for most of the drivers, foomatic, and typically cups for configuration and administration. The information found at linuxprinting.org (e.g. is my printer model supported?) applies exactly the same to Linux and *BSD. There are some drivers which don't come with ghostscript; a search through the printers section of freshports.org will show that FreeBSD doesn't lack in that department either.
As for contributions and documentation, the FreeBSD and PC-BSD projects work closely together and PC-BSD gives back many patches and enhancements to the FreeBSD project. In addition to the PC-BSD documentation, the PC-BSD refers to the FreeBSD handbook and there is a whole chapter on printing in the FreeBSD handbook....