Autocommit to off

Hello.

I have installed postgres 7.4, and I see that it's not possible to do
"alter database ... set autocommit = off"

In the documentation, I found:

Note:  The autocommit-on mode is PostgreSQL's traditional behavior, but
autocommit-off is closer to the SQL spec. If you prefer autocommit-off,
you may wish to set it in your .psqlrc file.
(http://www.postgresql.org/docs/7.4/static/app-psql.html)

My questions are:

- Where I must look for the file .psqlrc?  I must create it in a special
directory?
- What format must have this file?
- If I set this file, Do the applications (including ecpg) connect to
the database with autocommit = off????

Thanks for your responses.

CG