PostgreSQL for Linux, NT and Windows 98, from Access ?

Hi people.

I work for a company that manufactures a large database application.
Currently the "client" is written in VB/C++, using the DAO for data access
and the database format is Access, with stored queries. It works well, but
we need more scalability.

We want to convert the application to true client server. Sensing a
signicant (impending) Linux revolution, I am wondering if anyone has
converted an Access or SQL server based application to PostgreSQL (or
MySQL) and ran the server portion on multiple platforms, ie: NT, Windows 98
or Linux.

How difficult is the conversion from Access to PostgreSQL ? How well does
Jet/DOA work in ODBC mode with the PostgreSQL ODBC driver ?

What changes are needed in the PostgreSQL application (server) to make it
run on all three environments ? (I'm hoping to hear none !)

TIA,
Kim