Specifically, you can access the Solaris 10 OS Release and Installation collection at:
http://docs.sun.com/app/docs/coll/1236.1
Downloading Solaris 10 OS Software
If you need to install the Solaris 10 11/06 OS or reinstall the OS after removing it, you can download the CD or DVD image from the following URL:
http://www.sun.com/software/solaris/get.jsp
Solaris 10 6/06 is the minimum supported version for the Sun Fire X4150 server.
See the Sun Fire X4150 Server Operating System Installation Guide for specific instructions on Solaris 10 installation.
Solaris 10 OS Training
Sun provides flexible training options that accommodate your personal schedule and learning style. The training options include
http://www.sun.com/training/catalog/solaris10.html