I have the Westell 6100 wired DSL modem and have it connected to a LinkSys
switch- which is connected to 4 PCs. (all connected to the internet via
Verizon)

A friend dropped by with his Mac laptop and a Airport Express Base Station.
He says he could connect it to one of the Ethernet cables going to one of my
PCs- and it would make the system wireless, at least for his Apple laptop
which is configured to work with the Airport Express Base Station.

First of all, I was concerned about the Airport causing some problem with my
network- which almost caused me a nervous breakdown to set up (I had trouble
with trying to make the Westell work with a router- until someone here
recommended using a switch instead). If the Apple had a virus on it, could
that virus migrate to my other PCs?

If it's really that easy to turn my wired network into a warless network, do
such products exist to work with PCs instead of Macs?

Anything else I should be warned about if I allow my friend to hook up his
Airport Express Base Station to my network?

Joe