There's a patch that gives PG the Oracle CONNECT BY statement. That patch was refused by the PG core team because Oracle's CONNECT BY is:
1) Non-standard
2) Not as functional as the SQL 99 statements for hierarchical queries.
Or as Tom Lane would put it "Non-standard and broken."
So the PG team will implement the SQL 99 syntax. The Red Hat DB team (which Tom Lane belongs to) will do it, I think for 7.5 (don't think it made it to 7.4).
-Roberto