Has anyone here used Firebird or Postgres with ASP.NET?

Exactly what would be involved in this. I want to develop my database
in SQL Server (which I am familiar with and then convert to Firebird or
Postgres for deployment.

I realise that it may be next to impossible to find a hosting company
for this combination but what I'm interested in learning right now is
can it be done? Obviously the answer to that is yes but I also want to
know how to go about doing this. If this is the wrong forum for this
question then where should I ask the question? At the Firebird and
Postgres forums? Yes that's where I'm looking. But if anyone here can
give me advise about the suitability of Firebird vs. Postgres I would be
most grateful.