I've installed readline-5.0,REV=2005.06.07-SunOS5.8-i386.pkg, by using ./configure, make, make install. At the end it ask me "install: you may need to run ldconfig", but OpenSolaris doesn't have ldconfig.
I initally ignored that last message it and installed an application but keep giving me a warning: The <CSWreadline> package "CSWreadline readline" is a prerequisite and should be installed. -- This message posted from opensolaris.org