enable simple file sharing, this will allow your to share your printers and your files to your other computers and they will be able to see it, by default, both the guest and the simple file sharing is disabled.

Don't know if this will solve the problem but it does work very well.
http://www.apple.com/airportexpress/ And yes it works for PC also.

right click on My Computer on all of the PC's (not macs) and go to properties. Then click on the "computer name" tab. Make sure that all of them are in the same workgroup, the default name is WORKGROUP. If they're not, rename them so that they are and then reboot them.

you can also determine if all of the computers can see each other by pinging them.

go to start> Run and type CMD in the command box and hit enter

when the DOS box opens type

IPCONFIG /ALL and hit enter

the IP address for the computer that you're on will be displayed along with other IP info.

write that ip address down.

Go to one of the other PC's and go to START>RUN
type CMD in the command box and hit enter

then type

ping <IP ADDRESS that you wrote down> and hit enter

You should get 4 lines of "reply ......" and then some summary info.

Do that on all of the PC's (ping the PC with the printer attached) if the ping test is successfull at least you know that IP is working ok and that htey can see one another.

let me know how that goes.... and then we'll go from there

OK - did that, but when I ping the main computer, I get 4 "request timed out" messages. I only have 2 computers in the house right now - the main computer and my son's laptop (MS), so I'm just working with these 2 right now. I figure if I can get these 2 to see each other, I'll figure out how to get the rest.

OK, so what's the next step?

just to recap:

You went to the 2nd pc and typed in Ping <ip address of computer with printer attached> and it times out?

if so, can both machines get to the internet?
Did you try pinging the 2nd machine from the main machine?

make sure you're typing in the right IP address too. it's easy to thumb.

Interesting...

Yes, both machines can get to the internet, and when I ping the 2nd machine from the main machine, I can see it...

Turn the firewall off on the NIC card on the main machine.

Sorry for the ignorance - how do I do that?

Just found Windows firewall and it is already set to off...

Start>Control Panel> Network Connections

Right Click on Local Area Network Connection then select properties
then click on the advanced tab
then click on the settings tab
turn the firewall off

click ok until all of the dialogue boxes are gone

try to ping that machine from the laptop again