I just bought a second computer and I don't know how to connect to the internet. My lap top has DSL. What do I do?

You might want to consider a router. If your laptop has wireless capabilities the router might even allow you to use it in other rooms without stringing a network or phone cable. In addition to connecting multiple computers there are usually security advantages. Check the package to see what cables are included in case you need to buy an Ethernet cable to hook the new computer with (you may have one already between the DSL modem and the laptop)

Some of the router manufacturers have tutorials that help people learn about networking:

Welcome to Linksys.com Look for "Learning Center" on the menu
D-Link | Welcome Look for the D-Link TV links

Another manufacturer link:

NETGEAR - Wireless routers, adapters, and other networking solutions for the home, smb, and broadservice Providers

You might also want to check out Internet Security Source they have some programs for keeping your network clean.