Oracle and PostgreSQL

Hello my friends,

We are going to change some Oracle 8i and 9i databases to PostgreSQL 8 at my
company.

1st: Is there somebody who knows how to do it (had the same experience)?
What are the limitations of this process (eg: incompatible data types and
objects).

2nd: Which tools are available to do it? I've seen one called SQL Fairy
(http://sqlfairy.sourceforge.net/). Is this one the most recommended?

3rd: Is there a way to make both databases talk (such as creating a DBLink
between two Oracle Databases)?

And finally, do you know a good comparison chart or benchmark between these
two databases? A Brazilian university teacher made one
(http://www.ic.unicamp.br/~celio/livrobd/docs/benchmark.html) but I'd like
to see other comparsions like in real production databases.

C ya,

Teolupus