getting information of tables and indexes

Hi

                I am Srikanth.  I want to get the information about all tables in the existing postgresql . I want list all the tables and its columns information by executing a simple SQL statement like in oracle. We have a view like “user_tab_columns” in oracle to get all the information of  the tables of a user. Can we have nay option like this in postgresql can u help out in this.

            And also I want to get all constraints in the database and also respective parent tables and parent columns for the referential constrains. Please help in this issues.

            I will be thankful to you for your helping in this