Source code:

  1. Illumos_gate - https://github.com/illumos/illumos-gate
  2. X11 - https://hg.openindiana.org/upstream/oracle/x-cons/x-s12-clone/
  3. Package Manager/IPS - https://hg.openindiana.org/upstream/oracle/pkg-gate/
  4. Caiman Installer - https://github.com/OpenIndiana/slim_source
  5. OI-userland - https://github.com/OpenIndiana/oi-userland
  6. JDS/GNOME - https://hg.openindiana.org/upstream/oracle/solaris-desktop~spec-files/
  7. SFE - svn co https://svn.code.sf.net/p/pkgbuild/code/spec-files-extra/trunk spec-files-extra 
Docs:
http://www.oracle.com/technetwork/documentation/solaris-11-192991.html

Binary Packages:
http://pkg.openindiana.org

Distribution Snapshots (i.e. Get Hip!):
http://dlc-origin.openindiana.org/isos/hipster/

Books:
 
Oracle Solaris 11 System Administration
OpenSolaris Bible 
Pro OpenSolaris
Solaris Internals: Solaris 10 and OpenSolaris Kernel Architecture
Solaris Performance and Tools: DTrace and MDB Techniques for Solaris 10 and OpenSolaris

Solaris Troubleshooting Handbook: Troubleshooting and Performance Tuning Hints for Solaris 10 and OpenSolaris

DTrace: Dynamic Tracing in Oracle Solaris, Mac OS X and FreeBSD (Oracle Solaris Series)
OpenSolaris for users, administrators, and data centers: the first steps to productive operation on SPARC, PC and PowerPC-based platforms