if the folder you want to share with the other computers is "local" that is these computers will be on the SAME network as shared file, then it's easy.
It's recommended that they all be in the same workgroup or domain... then simply sharing them should do it. The OS you're using matters of course, XP home generally is very simple because it has no security when it shares. However, XP pro does have security and often even if in "basic" mode will sometimes require a username/password to gain access. I've seen that in home system too even though it's not supposed to happen. In either case the fastest solution is typically to just add an account with the same name as machine that wants access. For example, if the accessing machine's primary account is called "X" you'll want to add an account to the host machine called "X" with the same password. I know that's annoying but I've run into this bug too many times to avoid mentioning it.
if you're trying to share an internet connection that's completely different. Each network controller is separated by default... ie not connected in the computer. So if I'm logged into one network with my wireless card and another with my Ethernet or another wireless card these two networks cannot communicate with each other. If one of these networks provides internet, then the other networks will not be able to use my computer to use that internet... unless you explicitly link them.
There are two ways to do this... the easy way and the annoying wizard way... Prefer the easy way. :)
Easy way first:
Go to the network connections applet in the control panel, then select the two controllers you wish to link. If there are a lot there and you don't know which is which, then turn them on and off until you figure it out... then label them accordingly. Labeling them doesn't change anything but what they're called in the network connections panel. After selecting them, right click and choose "bridge connections".
that should do it.
Annoying wizard way:
Click on network setup wizard in the Network connections panel in the control panels. Follow the on screen connections... that should work too... though sometimes it has very weird results. I avoid it because of that and because it's typically easier to do it any other way.
