I've just installed Moodle on my Solaris x86 workstation after hearing about the performance problems some teachers were having running it on their Mac OS X server. It seems MySQL craters at over 15 connections on the new version 10.5 so they are forced to deploy onto linux in production.
After compiling PHP with the enable-fastCGI switch it's just a matter of configuring the JES Webserver for the PHP modules - similar to Apache.
You could of course use the Apache webserver bundled with your free download of Solaris x86.
Here it is running on my W2100z

Full configuration instructions coming shortly.
Now to setup authentication to the JES Directory Server...