If you ask Apple, dial-up modems are dead. Macs don't even come with built-in modems anymore. You can get an external USB modem for $50, but clearly, Apple is trying to shove the trusty dial-up technology into the recycling bin.
Still, millions of people never got the memo. If you're among them, you need to sign up for Internet service. Hundreds of companies, large and small, would love to become your Internet service provider (ISP), generally charging $20 or so per month for the privilege of connecting you to the great Internet.
Once you've selected a service provider, you plug its settings into the Network pane of System Preferences. You get the necessary information directly from your ISP by consulting either its Web page, the instruction sheets that came with your account, or a help-desk agent on the phone.
The following instructions don't pertain to America Online. It comes with its own setup program and doesn't involve any settings in System Preferences.
Open System Preferences and click Network. If your modem isn't already listed, click the + button at lower left; from the Interface pop-up menu that appears, choose External Modem, and then click Create.
Your modem connection now appears in the list at the left side of the pane. Click it. Now fill in the blanks like this:
Configuration. It's called Default at first, which is fine. If you like, you can choose Add Configuration from this pop-up menu and then name it after your ISP ...