Laptop Wireless

Hi everyone. Simple question. My mom recently bought a laptop equipped with a wireless adapter built in (g/b). I know how to setup wireless networks, but i have never done it like this without installing hardware. She is taking a trip this weekend and would like to have wireless internet access. I know that she needs to be near an access point, but how does it work in terms of connecting to them?

Obviously the free ones you are already connected, but in terms of the ones you have to pay for. I dont know anything about this because i've only set up home wirless networks that had DSL or Cable in them... never something like this. Do you subscribe to a company and search for access points that they have? What companies? ETC ETC...

i just need to know so i can attempt to explain it to my mom (shes a web designer who has no idea about networks and how to setup/work them.)

TIA!