Official FreeBSD sites:
The FreeBSD Project : http://freebsd.org/
The FreeBSD Foundation : http://www.freebsdfoundation.org/
The SpreadBSD Project : http://www.spreadbsd.org/

FreeBSD based operating systems:

PC-BSD : http://www.pcbsd.org/
DesktopBSD : http://www.desktopbsd.net/
FreeNAS : http://www.freenas.org/
Frenzy : http://frenzy.org.ua/eng/
pfSense : http://www.pfsense.org/
m0n0wall : http://m0n0.ch/wall
DSBSD : http://www.damnsmallbsd.org/
FreeSBIE : http://www.freesbie.org/
RoFreeSBIE : http://www.rofreesbie.org/
TrueBSD : http://www.truebsd.org/
askoziaPBX : http://www.askozia.com/pbx
TrustedBSD, not really an OS : http://www.trustedbsd.org/

Documentation around FreeBSD:
FreeBSD Frequently Asked Questions : http://www.freebsd.org/doc/en_US.ISO8859-1/books/faq/
FreeBSD Mailing List search engine : http://www.freebsd.org/search/search.html#mailinglists
FreeBSD on Wikipedia : http://en.wikipedia.org/wiki/Freebsd
BSD on Wikipedia : http://en.wikipedia.org/wiki/BSD
UNIX on Wikipedia : http://en.wikipedia.org/wiki/Unix
PC-BSD on Wikipedia : http://en.wikipedia.org/wiki/Pcbsd
FreeBSD wiki (Users) : http://www.freebsdwiki.net/
Freebsd Wiki (Developers) : http://wikitest.freebsd.org/

Comparison of BSD Operating Systems Wikipedia page : http://en.wikipedia.org/wiki/Comparison_of_BSD_operating_systems

FreeBSD Guides : http://www.bsdguides.org/guides/freebsd/
Defcon1.org - Howtos and scripts : http://www.defcon1.org/
Chucktips - FreeBSD site for newbies (tips and howtos) : http://lantech.geekvenue.net/chucktips/
The FreeBSD Diary - FreeBSD howtos and forum : http://www.freebsddiary.org/
UnixCities - FreeBSD tutorials : http://www.unixcities.com/
Screaming Electron : http://www.screamingelectron.org/
Screaming Electron’s howtos : http://www.screamingelectron.org/forum/archive/index.php/f-15.html
The Labs: FreeBSD mini howtos : http://www.the-labs.com/FreeBSD/
FreeBSD howtos at O’Reilly Networks (ONLamp) : http://www.onlamp.com/topics/bsd/FreeBSD
FreeBSD How-To's for the Lazy and Hopeless : http://flag.blackened.net/freebsd/
Tuning FreeBSD for different applications : http://silverwraith.com/papers/freebsd-tuning.php
Dru Lavigne's howtos on various topics regarding FreeBSD : http://www.onlamp.com/pub/ct/15
FreeBSD tutorials : http://freebsd.peon.net/

Blogs:
FreeBSD News Blog
BSD Planet - Syndicates feeds from major BSD sites and some BSD blogs : http://people.bsdplanet.net/
BSDpants : http://bsdpants.blogspot.com/