I can definitely see where it can get confusing though. This page:
http://store.apple.com/1-800-MY-APP...rowse&mco=3929D548&node=home/specialdeals/mac
Lists all available refurb products. And if a particular model isn't in stock, it doesn't really tell you that, so you kinda have to know what to look for.
Anyway, to answer the OP's original question:
There are three main methods of connectivity on the Powerbook/Macbook line: wired ethernet, wireless (WiFi) and bluetooth.
For wired ethernet, you'll need a broadband connection either at home, or provided by your college or workplace. Most colleges offer wired connectivity in dorms. And SOME IT-heavy workplaces,
might allow you to plug in a laptop of your own.
At home, you'll need to get either DSL or a cable modem. most phone companies will offer a basic DSL package for around $15-$20 a month, which is about 3-5 times faster than dialup. DSL and cable also offer much higher speeds at higher prices.
For Wireless internet, you'll need a WiFi hotspot nearby. Some local businesses, independent coffee houses, and
Panera bakeries offer WiFi internet for free. Others like Starbucks offer it for a fee. And you can get WiFi at home using a DSL/cable modem connection (see above) and a wireless router. A cheap one
can be found here. If you want something a little more high end,
you can get an Airport router.
Lastly, there's bluetooth. This is suitable if you have a data-enabled cell phone that's bluetooth capable, and the right data plan with a cell phone company. In this method, you connect your Powerbook to your cell phone via Bluetooth, and use it like you would a dialup modem. The instructions tend to vary depending on which cell phone company you're with, as do the speeds (anywhere from dialup modem speed to as fast as DSL). This can be the most expensive route, but it does allow you to get internet access just about anywhere you get a cell phone signal. I tend to use this when I'm traveling, and the hotel I'm at either doesn't offer WiFi (not very common) or wants to charge for it (more common).
Hope this helps!