First Wireless Network
When I eventually get my Linux machine up and running I intend to network it with the existing Windows PC in my house (mainly for internet sharing reasons).
The reason I want to do it wirelessly is because it will be going from one end of the house to the (literally) other end of it and I don't want a crossover cable going through the hall, up the stairs and into the room.
On the Windows PC I have a 1Mb Broadband connection connected to the PC via USB.
What extra hardware will I need to be able to link the two machines wirelessly for as little cost as possible?
There's two methods you can use here. I'll give you my preferred method first, even though it will be a little more expensive.
Method 1. Pick up a wireless router and wireless network adapter. The wireless router will have a 4 port switch built into it (at least all of the ones that I see have them). You can use your existing cat5 or whatever the cable is to connect to you Windows PC. You will then have to load the wireless network adapter onto your Linux PC.
Method 2. I've never done this, but have talked to people that have. You would need two wireless network adapters to set up an "ad hoc" network. I've never been interested in doing this, so I don't know much more than that.
FYI, you will need to set up some security on your wireless network, otherwise your 10 year old neighbor is going to go nuts downloading mp3 and pr0n on your internet connection.
I'd recommend hilowe's first method, even though it's a bit more expensive. It should be easier to setup. The main reason, though is that it's easier to expand later (say if you later want to setup a server, you could easily connect it to one of the ports on the router) and gives you (possibly) some nice options, such as a hardware firewall and/or printer port in the router (this all depends on how much money you are willing to spend). Also, I've noticed routers have a bit better range than those pci wireless network cards (which you would put into the windows computer if you were going with method 2).
i also recomend the first method. since ad hoc networks can be unreliable