Does anyone have a link or could talk me through setting one of these up?

I have Regular BB on a PC and the Mac, but only one at a time.

I require each of the other computers to connect via wirless/airport to the other systems BB

get a wireless bb router of the appropriate type (ie with built in modem for adsl or cable).

Both machines need a wireless card.

They should both be able to use bb simultaneously then.

Getting them to talk to each other will be more problematic and isn't something i've any experience of.

I borrowed a mac a few weeks ago and plugged the ethernet cable into my bb wireless router, it worked fine with no tweaking. I also instantly managed to find my pc's shares with the mac, which just mounted the folder/s on the desktop.
Seriously thinking of doing away with pc's!

Just do away with Windows, pretty much the same thing...