Query with Dynamic tables

[ i posted this originally to the pgsql-sql list, sorry for cross posting ]

I have a large number of tables with a common naming convention

mytable001, mytable002, mytable003 ... mytable00n

I would like to do a query across all of the tables, however I do not know
all of the tables before hand, and I do not want to ( cant ) manually
generate a query like

select * from mytable001, mytable002, mytable003

I have a query that returns the names of the tables I want to query:

select tablename from pg_tables where tablename like 'mytable%'

We use the table as a logging repository. It can get very large 250
000+ records. Because of the large number of records that we have in
the table we found it was much faster to perform inserts on a smaller
table. Our current system rolls the tables over every 12 hours or
so, creating a new table with the following behavior:

CREATE TABLE mytable_temp {...}

ALTER TABLE mytable RENAME TO mytable_NNN;
ALTER TABLE mytable_temp RENAME TO mytable;

I want to join the mytable_NNN tables together in order to perform
queries against my huge set of data to generate some reports. I'm
probably going to create a temporary table with a few indexes to make
the reports run faster... however I need to join the tables all
together first.

I know this is possible, because i've done it with postgresql before!

Thanks