or anywhere else by illicitly connecting to someone else's wireless network is a criminal offence, and isn't to be recommended - not that I'm suggesting you are planning to do it.
The is the standard home and business wireless networking technology, and your PCMCIA wireless networking card will use it.
Most business wireless networks operate on what's called 'infrastructure mode' which goes via a wireless access point, and is more secure - it means that you can't access the network from that coffee shop unless you are an authorised user on the domain - you'll need a login username and password. In addition, business networks will have WEP technology in use - WEP stands for Wireless Encryption Protocol. This technology provides heightened security, but at the expense of speed - it can slow the network down if there isn't some pretty hefty processing power in the wireless access point.
At home, your wireless network will operate in Ad hoc mode - which means that any computer with a wireless network adapter operating the 802.11b standard will be able to join the network if it's in range.
In practice you don't need to worry about people sitting outside your house in cars with laptops - stealing your precious ADSL bandwidth, or looking at your holiday snaps. That's the stuff of urban legend. Such people would:
a) Have to know you were operating the network in the first plac.
b) Have a laptop with a wireless network card installed.
c) Be in range
d) Be sad enough to want to sit hunched over a laptop outside someone's house in the first place.