How do i setup a LAN connection between two computers???

Ok, i have no clue about LAN connection. Consider me as an ablsolute layman and help me with my problem.

The Situation:

I have two computers, both working on Windows XP. Both of them are independent as of now. I have a BSNL broadband connection. The thing is, suppose computer B is connected to the internet,and if computer A is to be connected to the internet, i have to manually unplug computer B's data cable from the modem and insert comp A's data cable. This is frustrating as only one computer has access to the internet at any given time.

Both the computers have ethernet cards.

The Questions:

1.%26gt;How do i setup a internet connection so that both computers can have access to the internet independently?

2.%26gt;How much would it cost me? What brand of router(?)/switch(?) should i go for?

3.%26gt;Also i came across USB networking between two computers. Is it an efficient way of connecting two computers? If yes, how do i do that?

How do i setup a LAN connection between two computers???live update

You can setup B connects to A and A connects to the Internet. This way you will have to have 2 ethernet cards in A: one card connects to the Internet and the other will connect to B. From there you will have to configure IP and subnet mask and enable ICS (Internet Connection Sharing). You use a crossover wire to connect B - A. You use a regular RJ-45 straight through cable to connect A to Internet.