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
without providing a printer name argument.
That ought to do it.