Home network

I have a verizon wireless router connected to my main computer. This computer also has a printer I have two other computers upstairs in the bedrooms, each connected to the internet by a wireless linksys desktop antenna. They all connect to the internet fine, but they don't seem to see each other, and therefore don't share files or the printer. What pathway do I follow, in order to connect them, so that I can see three computers on my network? How can they share the same printer?

i found:

Printer sharing

and

Simple file sharing

and

Wireless Info

link 2 should work for wired or wireless…

I believe that they all have to be in the same work group. Note that you will have to restart the computer after changing it's work group for that to go into effect.
XP
Vista