NTP (albeit an older version) is distributed with Solaris in /usr/sbin/ntpd. Place the configuration file in /etc/inet/ntp.conf.
If you want to run a modern version of NTP, you can download/install it like you would on any other platform.
sunfreeware.com will also have downloadable packages.
--
Darren
If you download a new version, I'm not sure if svcadm will work... May require additional configuration?
Also, running ntpdate is unnecessary as (the Solaris version anyways) automatically does the equiv. to ntpdate when xntpd starts. Once running it keeps your system synched and no further commands are required.