This one bugged me too. Here's the thing. On the desktop, there's a setting in cups.conf that allows sharing (let me find it for you)... you should uncomment the line that says @ local in the browseaddress section... It will allow printing from all local machines.
Here's the section:
# The @LOCAL address broadcasts to all non point-to-point interfaces.
# For example, if you have a LAN and a dial-up link, @LOCAL would
# send printer updates to the LAN but not to the dial-up link.
# Similarly, the @IF(name) address sends to the named network
# interface, e.g. @IF(eth0) under Linux. Interfaces are refreshed
# automatically (no more than once every 60 seconds), so they can
# be used on dynamically-configured interfaces, e.g. PPP, 802.11, etc.