when entering the postgres shell, you can use normal SQL commands (there's a good SQL reference included in the postgres documentation)
use this to view data:
select * from <table>;
or with criteria:
select * from <table> where <field>="<value>";
I don't use pgadmin but i thought it had a function to view the data... not sure...
and so on and so forth... you should really dive into the SQL language and syntax
greetz,
-= iluvatar =-
ps: dont forget the ';' dot-comma at the end of a line, this will make postgres execute the line