The basics of wireless networking (please!)

Hello all. I have three laptops and I have always had a **** of a time getting them to talk to each other wirelessly. The wireless router is a Belkin and works fine, I don't think there are any issues talking to/via it. The main issue seems to be passwords, and what the computers are called, or rather, call themselves, since I don't remember giving them names! Additional complication perhaps, two of them were bought second hand, so may have had some passwords buried deep inside.

With two of them I have persuaded them to each have access to the other's public drop boxes, but they won't connect as other than guests, which doesn't help much. The third one, and why I'm here hoping this situation can be fixed at last, will connect to the point of asking for a password as a Registered User, doesn't understand the password (there isn't meant to be one) and when I try Guest it says Select the volumes to mount but shows precisely nothing! Trying the same thing in the other direction does get the Drop box but really I need access to the desktop etc etc!

I guess the simplest help would be a step by step process describing where the names of the machines can be set so they can't be confused (they're all basically G4 powerbooks after all) where any passwords may be set, and what needs to be set how so these machines can have data shared between them without a drama each time, I don't need passwords, there are no security issues here. It would be so neat to be able to actually use the system as it should be able to be!

Having written all that it sounds like a monster job, so I do hope somebody's got the energy!

Many thanks

Stephen