Developing for Multiple Databases: PostgreSQL and Oracle

Currently we develop apps on Oracle and MySQL but we are about to add
PostgreSQL to the list. Among the many wonderful advantages of using
PostgreSQL over MySQL ,(I am painfully aware of the problems with MySQL's
lack of subselects and ANSI SQL), I think it should be a lot easier to have
Oracle/PostgreSQL as database development platforms than to have the
Oracle/MySQL combo. Can anyone corroborate this?

There seems to be a lot of similarities between Oracle and PostgreSQL and as
an Oracle_Hack/PostgreSQL_Newbie I see a lot of nice PostgreSQL functions
that look like Oracle. For instance I see that both Oracle and PostgreSQL
use the same to_char and to_date functions so any code using date/time data
types should be portable.

Any tips or gotchas on developing database portable code on PostgreSQL and
Oracle? Any white papers or web sites that address this issue?

We develop with Oracle Pro*C and the MySQL C API so I'd be interested in the
C API support for PostgreSQL and the ability to develop portable embedded
C-SQL.

AtDhVaAnNkCsE !!!
Steve Orr