ej-
What Angel said will work, but there is another option.
Buy a wireless access point that has a built in router, like the Linksys BEFW11S4. It is a wireless access point (WAP) and a 4 port switch / router combination.
Your cable modem plugs into the Linksys BEFW11S4. Up to 4 other computers can plug into the Linksys using regular old ethernet and it will act as switch (which is better than a hub). You also need a wireless network card for the notebook, which will interface with the Linksys BEFW11S4 wirelessly on the same network.
The linksys unit can have a bunch of computers hooked up to it wirelessly and four wired connections. All can access the internet via the cable modem and all can share files and printers.
This is not the cheapest option - the above mentioned Linksys router / switch / wireless access point goes for about $170 and wireless network cards for notebooks are $75-100 each. Your current network card in your PC can hook up to the router without any changes. Personally, i'd buy the WAP and wireless network card from the same supplier for ease of use.
I recommend this setup for several reasons. #1 is that the wireless access point is the most most expensive part of the equation and will cost at least $140 on its own. Buying a WAP with a built in router / switch doesn't increase the cost all that much. #2 - some cable modem companies aren't real keen about letting you have more than one computer access the internet without charging more money for the privilege. The router aspect of this equipment makes it look like you only have one computer. #3. The router also acts as a first defense against hackers / intruders - it has a built in firewall type defense.
A regular WAP won't necessarily have a router built in.
The reason i recommend the linksys unit above (as opposed to netgear or someone else) is because that is the setup i am using at home and it is working very well. I have 3 computers hooked up via ethernet cables (all in the basement, with the WAP), and i use one laptop anywhere in the house. All the computers can see each other, share printers and most importantly, share the cable modem internet connection. There are other companies that offer similar products at similar (maybe even lower) prices, so shop around. (I got mine a buy.com).
I hope i have explained this well. If not, please post another question or maybe do a search on this site for previous posts about wireless networks.
Tommy