Beta 2 of plPHP has been released. This version contains many bug fixes. For example, if you write bad plphp code and try to execute it, the code will no longer crash PostgreSQL ;).
The URL is here: http://www.commandprompt.com/entry.lxp?lxpe=260
There are precompiled binaries for RedHat 9. There are general compilation instructions.
Sincerley,
Joshua Drake