After you install Indiana May Release (OpenSolaris 2008.05) in your box, you may need install the following packages to setup your box as a Gnu/Gnome developer desktop:
$ pkg install ss-dev SUNWxwinc SUNWxorg-headers SUNWgnome-common-devel \
SUNWperl-xml-parser SUNWiconv-unicode SUNWiconv-extra SUNWgit
It's a little strange, that the gtk/gnome header files are shipped in the liveCD and got installed by default, but not the X11 headers (in SUNWxwinc).
Besides that, you may still need the CBE. If you already have the installation on other machine, directly copy them to your box could just work. Or, pkgadd(1) is still available to install the SVR4 packages.
Thanks laca posting the instructions for building Gnome packages for Indiana. And you may refer to moina's blog for building FOX packages. And migi's excellent tutorials are also very useful for you to understand how the packages are built and transfered to IPS repository.
Today, I installed indiana preview release (get it here) on an existing solaris partition. And the installation time is a little longer than I expected. The only one issue I met is, after the installation, grub was not installed properly. So, we have to use
installgrub(1) to reinstall it on MBR. The root password on livecd is "opensolaris".
Currently the software package repository is still small (have a look at http://pkg.opensolaris.org.) Anyway, it's the first step (also an important step), and I believe it will lead opensolaris to bigger success.
BTW, you may try to install Glassfish packages via IPS, refer to http://wiki.updatecenter.java.net/Wiki.jsp?page=MultiPlatformIPSPrototype.