Only a couple things you need to do.
Does your notebook have a built in wireless card? If it does, that'll save you some money, otherwise you'll need to buy a pcmcia wireless card. You'll also need to purchase a wireless router. Your cable modem will plug into the the router (some have wired ethernet ports as well). You generally want the wireless router to sit up in an elevated place relatively free of surrounding clutter.
There are a few standards to know. 802.11b is the plain jane, 11mbps. 802.11g supports 54mbps. It's really up to you. I knew my wireless network (2 notebooks) wouldn't be on constantly using bandwidth so I opted for the cheaper route of 802.11b gear. However if you want the latest and greatest speed, 802.11g would be the way to go, albeit more expensive. You just have to make sure your PCMCIA card and wireless router use the same 802.11 standard, A,B,G whatever.
Example: I have Microsoft's MN-500 Wireless Router (802.11b). It claims 160ft indoors and 900ft outdoors. But that is a pretty open line-of-sight. The router sits in my bedroom and I can go to my living room which is no less than 20-30 direct feet away and still get some signal loss due to many walls. However if it's only a few walls and/or obstructions, you should still get good-to-excellent signal quality. You can go a pretty fair distance (I went outside, outside my window and was able to get a decent signal) but if it's any monster distances you may have to pick up a signal booster.
My router also came with a nice setup guide, detected my broadband connection, set encryption keys easily, etc. Then all you'd have to do is install the card in your laptop (Windows will install most of them) and run network setup wizard and tell it you're connecting wirelessly. It'll ask you what you named your network, to input your WEP key, what channel it's broadcast on, etc., and you should be good to go!
You want to read carefully in your router setup guide on securing your network when you get it up and running also. Most people employ a strong 128-bit WEP key and turn off SSID (this is what broadcasts your network's name). Most wireless routers will have an option to "log-on" into it so you can change security settings, enable firewall and ping blockage, TCP port-forwarding, all fun stuff.
Did I complicate it enough for you?
