If you want to share your connection from your PC you'd just use Windows ICS or some other NAT/proxy software. You could get a wireless card for the LAN side and another wireless card for the laptop and run the cards in Ad Hoc. That would be the cheapest route. The preferred method these days is buying a SOHO router. In your case you'd get a Router/AP combo. These normally come with some switched LAN ports so you could continue running wired from your desktop and just get a wireless card for your laptop. This is not really that much more money that the two cards idea and in some cases might even be cheaper, plus you'd have a built-in firewall and wouldn't have to have your desktop on for the laptop to be connected. Any of the SOHO vendors make AP/Router combos. D-Link, with their 802.11b+ (22Mb) radios seesms to be the hot Wi-Fi item right now. Good range, speed and price.
I'm also a newbie and I have the same doubt. I have access to the internet through a LAN. Now I'm using a regular ethernet cable and a hub to connect both the PC and the laptop. But I want to buy a PCMCIA wireless card so I can take my laptop anywhere at home.
Anyway, what do you mean by a 'wireless router'? Do you have any links where I can see one? Does it work like a hub where you can attach regular cables on it also? This card must be connected to the PC or can it work stand alone?
The wireless router As defined by jlanka will do everything you need. They typically provide you with 4 ports and wireless. You will need that and 1 wireless PCMCIA card. Whole thing should cost less than $180.
It may say I'm a NOOB but I've been hiding in the shadows @ THG since 97.