Although Solaris is dying somewhat in the hacker space, SunOS/Solaris used to be king of the hill in the unix hacker community. There is still a core of Solaris people on usenet and quite a body of online literature. Solaris is also a fairly mature, stable platform so much of the archived historical material is still relevant in a way that 10-year old docs on Linux might not be.
Getting started with OpenSolaris 2009.06 (free) provides an introduction to the OpenSolarisTM operating system, as well as instructions for installing and configuring the OpenSolaris release;
Ben Rockwood's blog - online & free
Sun BigAdmin - online & free, but may link to non-free Sun stuff
Blog O’ Matty
More than Solaris but I've found some real gems on his blog (like Oracle Sun cluster information).
Check out the LKSF book here.
The best way to learn is to dive in to it. Install OpenSolaris on a Vm and work away.
Although Solaris is dying somewhat in the hacker space, SunOS/Solaris used to be king of the hill in the unix hacker community. There is still a core of Solaris people on usenet and quite a body of online literature. Solaris is also a fairly mature, stable platform so much of the archived historical material is still relevant in a way that 10-year old docs on Linux might not be.
The Sun Freeware site: http://www.sunfreeware.com/ is indispensable and free.
The opensolaris forums are a logical place to start if you have specific issues:
http://opensolaris.org/jive/index.jspa?categoryID=1
I often find useful stuff on blogs.oracle.com, but it's not exclusively opensolaris of course.
The community documentation feels a bit dated in many places, but is still extremely useful.
http://opensolaris.org/os/community/documentation/