Stored procedures - how to start

Hello,

I really like the concept of PostgeSQLs functions.  But what do
I have to do if I like to get a whole table, i.e.  how to
perform a

    SELECT * FROM <table> ;

in a stored procedure.  I wrote servlet code with many stored
procedures for MS SQL server and now wondering, how to port those
things but failed to find something in the docs.  Could someone
give just a short example (may be how to do the SELECT above)
or give a hint to docs.

Kind regards

         Andreas.