Lol @ diagram!

Right, so I asked my mate, who sets up wired and wireless networks for a living, tonight for the low down on it.

He says I am kinda on the right track but a little off.

It doesn't matter if its a built in wifi or "plug in" wifi (pcmcia or usb) laptop - both will connect to the net if a WAN signal is found. But only if it is decrypted - basically "open" as a free for all.

If the WAN network is encrypted - basically it's a private network and PC's are assigned to it - then you won't be able to connect to it.

But if it's say, on a Virgin train or in a posh business hotel/conference centre/office or whatever, you might find a decrypted WAN service which will allow you to hook into it and get internet.

There are plenty of hotspots all over the pace where you can pick up decrypted WAN services - you just gotta find em and remember em