Since you have only a dialup connection, your wireless will not connect. I presume that you are using Win XP.
Go to Start > Settings > Network Connections > New Connection Wizard.
Proceed and choose Set Up My Connection Manually.
Connect using a Dialup Modem.
Choose the modem and proceed using your Login and Password.
It should be enough to get you on internet.
I live in a rural area with dial up internet. I recently purchased a Dell Studio 1536-150P Laptop with Wireless. I installed our ISP, Netzero on the laptop and plugged in the phone line, but it won't connect to the internet. Is there an internal setting in the laptop that should be changed in order to keep the Wireless when I'm not at home AND also use the dial up connection when I am home?