Knowing new item in table...

im still in the dark when it comes to postgres..... is there a way i can
know if there was a new entry on a table...

scenario...

i have a script that runs every 5 minutes... that script checks if there's
a new entry in that table... and if YES there's a new entry ill do some
processing...

is there an internal utility that i can use in postgres that can tell me
that this rows a new commers... hehehe....

if someone has other ideas on how to deal with this speak out...

thanks in advance......

btw..
my idea is that that table will have an addtional column as reference
lets say column "READ" 1 for yes 0 for NO