Hi and welcome to the::unwired and your questions is nothing you have to excuse for!
What you are looking for is a "PCMCIA" or "PC Card" modem which is available for GSM, GPRS, EV-DO and UMTS.
Basically this PC cards works like mobile phones except they don't have a screen nor a battery but you plug it into the laptop. Therese cards come with a piece of software which allows you to enter the PIN, to select the network as well as creating a data connection to the Internet. Once connected, you can do mostly everything you can do from your Internet connected home PC as well, browsing the web, sending and receiving E-Mails, etc...
So yes, you need a PC card, you plug the SIM into this card and after you plug the PC card into the laptop.
I suggest you visit Option who is well known for their data PC cards to get an overview what is available in general. However, availability depends on your location (country), carrier you have a contract with and technology your carrier supports (GSM, GPRS, EDGE, UMTS, HSDPA, EV-DO etc.).
If you have any further questions, please feel free to ask us anytime!