Sun has released Solaris 10 Update 3 (11/06) and it is available for download.

Ben Rockwood has a nice list of new features and enhancements:

NIA Multipath Management API Support
fsstat File-System Monitoring Tool (Very handy indeed!)
ZFS Command Improvements and Changes, including RAIDZ-2, Hot-Spares, Recursive Snapshots, Promotion of Clones, Compact NFSv4 ACL’s, Destroyed Pools Recovery, Error Clearing, ZFS integration with FMA, and much more.
Resource Pools now SMF’ized
Zone Renaming, Moving, Cloning, Import and Export
Logical Domains for sun4v
Solaris Trusted Extensions
Support for PCI Express
Sun Fire X4500 SATA Disk FMA
Adobe Flash Player Plugin for Solaris
Solaris Trusted Extensions Desktops
Solaris Flash Archives Improvements
Secure By Default Network Profile
ST Driver Support for Quantum LTO-2 and LTO-3 Tape Drives
IIIMF and Language Engines Improvements

The What’s New documentation at Sun has the full list of changes.