I know that this is the next big thing in computers, being able to access wireless networks and get on the internet that way with your laptop. How does this work? I hear people talk about being in a “hot spot” where you can be on a wireless network, but how do you know when you’re in one, and how do you then access it? Is it free? What software do you need for this?
The one thing I do know is that your computer needs to have the wireless networking adapter.
I am no expert, but I got an access point router and a wireless card for my laptop. When I boot up the laptop, it detects my network. It occasionally detects my neighbor’s network too.
When it detects a network, a little balloon pops up (Windows XP - I don’t know how other OS’s handle it) and then I can click on the balloon and the list comes up of available networks, and I choose mine and connect.
There’s a bunch of security things to be concerned with, I have only had this set-up a few days so someone more experienced will have to advise you there.
Usually the place you’re in will tell you if they have a WAP(Wireless Access Point). Alot of coffee shops and college campuses have them. I’ve never experimented with wireless networks, so I don’t know that much either. Just what I’ve read.
I should add (so it’s not too confusing) that my access point router is connected to my desktop computer and my cable modem. So it’s not like I’m pulling the signal out of nowhere. 
I am guessing you are wanting to know more about wireless access in public areas. There is warchalking (Google it), I’m still awaiting an A-OK from the mods to see if that is OK to talk about here.
I should point out that it not really a good idea to walk around with dhcp enabled on your laptop, randomly connecting to other peoples networks.
The legality aside, you might just come across someone nasty (unlike me) running a dhcpd on their laptop…and while their machine is nicely secured running OpenBSD, your own might not be quite so closed…
FWIW, discussing warchalking ought to be OK, as it’s not illegal. If anything, the warchalkers ought to tell the chalkees what they find, so networks that were believed to be private can be better-secured.
As for the “hot spots” they’re usually free, provided as a service by the coffeeshop. The cost to set one up is trivial, from a business promotion standpoint - $200 or less for the WAP (Wireless Access Point) and around $75 a month for a good business-class broadband connection (DSL or cable) Or, if they’ve already got a T1 line running, just plug into that.
As described above, Windows XP will merrily log itself into any damn network it bumps into and give you a little balloon message on the taskbar saying it’s connected. From a security standpoint, this is bad news - depending on how you have public folders set up, someone could start rummaging around your folders without your knowledge.
The two “biggies” in securing a wireless net are to enable what’s called “WEP” or Wired Equivalent Privacy, and a good password on the SSID. A “good” password would be something bizzare and random like f&3pt*M - a mix of upper and lower case, numbers and punctation, as well as not a real word. Dictionary-based crackers can stare at that all day and not get a clue. Also be sure to have a good password on the WAP’s administrator account. Probably 98% of the WAPs in use now have the admin password set to a default such as “admin”
If you want to be really paranoid, you can enable MAC Filtering, which involves entering the MAC ID of each network adapter allowed to access the network. MAC is essentially your network adaptor’s serial number. This works well for small nets, but it becomes really labor-intensive on larger nets to enter and keep track of them all.
Most makers of wireless networking gear have info and tutorials on security, and are worth reading through if you’ve got a wireless net at home.