First time Wireless User

OK I bought a Laptop at Best Buy. They tell me it is all set up for Wireless web access. When I click the Network icon at the bottom right of my desktop it says I am currently connected to "Network" which I assume refers to my current broadband cable modem. If I select "Connect to a Network" the Connect to a Network Box pops open and it lists 4 or 5 networks to select from. They are all security-enabled networks and if you try to connect they ask for a password.
I am assuming this is because my computer is picking up somebody else's wireless network and they smartly have it protected?
I am connected to the web via Wide Open West using a Webstar DPX100 cable modem. Is there a way for me to access the web in my home without having the line from my cable modem connected to the computer? I'd like to use my computer throughout the house not just at my desk.
Thanks!
Brian

For 50 to 100 $US you can get a wireless router that will allow you to connect multiple computers, both wired and wireless, to the internet.

Whether this will cover your whole house wirelessly depends upon the placement of the router, the size and shape of your house, and the obstacles the signal must overcome. Those obstacles include metal in the walls, wireless phones, and neighbors' wifi routers.

Out-of-the-box, most wifi routers will only give you a clean connection 0-3 rooms away, because walls destroy the signal more than distance. More people are disappointed with their wifi range than are pleased with it, but they wouldn't go back to being wired in, either.

Buy a wireless router and set up a wireless network, that's all..

This tutorial would help..

Wireless Network Setup Tutorial

Hope helps..