Creating an odbc connection... needing help

Hello, i know you are experienced people working whit the postgres ODBC, but
i know too that is the better place to make my question, so forgive me if
you don't like it.
I am new working whit Postgres, but i want to develop an gtk application
using the postgres data base. I actually have the IODBC ADM, but it doesn't
have the postgres odbc driver added, and i don't know how to do it. I saw in
some web pages that i must to configure the odbc.ini file, but i don't know
how to do it, but the think i want to know is if configuring the IODBC ADM,
the odbc.ini is updated.
Oh, i forgot to tell you that i have the Postgres v7.0.3 installed in my
Linux SuSE 7.0, also i have the ODBC, JDBC, TCL/TK and HEADERS of the
lastest version installed
too.
How can i do to access my DB whit an ODBC connection?
and how can i configure de ODBC to do that?
Thanx.

Please i would thank all the help you can give me.
THANX A LOT...