MS SQL <=> Postgresql

Greetings!

Unfortunately, I know little about both products (training for (wrong :)
one happening next month)...

We have a mission critical DB running on MS SQL that I'm planning on
porting across to PG. To play it safe, I'm planning on installing a LINUX
box with PG at a satellite office to see how it goes.

Question: Last week you mentioned how to get MS SQL to update PG. Is it
possible to do the opposite (so PG updates MS SQL), or does this happen
anyway? If it doesn't, how can I do it (a pointer to a HOWTO or useful web
site will suffice :)

BTW, unfortunately, I came in part way though last week's discussion, and I
can't find it referenced in the archive index ... :(

Thanks.

Dave Burbidge
Network Administrator