If you've tried to administer and minimize your Solaris installation, I'm sure you've hit the problem that is easily listing a pkg's dependencies. Well, not any more. An 8 year old request for enhancement (RFE)...

5012345 request for tool to list package dependencies (My Oracle Support login required)

... has just been implemented in Solaris 10 and is delivered with patch 119254-84 (SPARC) and 119255-85 (x86).

This patch introduces the /usr/sbin/pkgdep command with the following usage instructions:

# /usr/sbin/pkgdep

Usage:
/usr/sbin/pkgdep [-v] [-c | -m metacluster] [-d package-directory] 
   [-p product-image-path] [-R root-path] package-name

The following options are supported:
-c	Print only dependencies not currently installed on the system.
-d	Specify a directory to check for packages and dependencies.
-m	Print only dependencies not included in specified metacluster.
-p	Specify a product image to check for packages and dependencies.
-R	Specify an alternate system root.
-v	Print full package descriptions.
#

As the usage message indicates, the usage itself is not very complicated. If you're curious, this is a Perl script, so if something isn't working as you expect, have a look at the source and see why.