I have read this article from linuxpipline (http://www.linuxpipeline.com/163700463).
It talks about a startup company named EnterpriseDB, which is developing an Open Source
DB based on PostgreSQL (http://www.enterprisedb.com/index.jsp).
They claim to support Oracle-style features like SQL syntax, datatypes, triggers, and stored procedures.
They have released a beta for download.
Sounds interesting, I will update you after I haved installed and played with it.