CUPS problem

After a lot of problems with printing I followed the advice in a posting a few days ago and installed CUPS It seems to be working fine. I can acess it from a browser and configure the printer and print test pages. But when I try to print using lp or lpr I get the message: error - no default destination available. So my question is: how do i get my system to use the CUPS that seems to be working OK? Olle Viksten