You need to set up CUPS.
As root, start a browser and go to
http://localhost:631 (CUPS administration). Choose the
PRINTERS tab and walk through the individual settings (there are drop-down menus and the like to help). Pick your printer model (most of 'em are there), and use
socket://192.168.2.157 for the connection. Also, be sure to select
Set as Default (on the
PRINTERS screen) so you can use
lp or
lpr without providing a printer name argument.
That ought to do it.
