No Set Text, but One Useful Reference…
A good reference for the economics of information technology is Information Rules (1999) by Carl Shapiro and Hal R. Varian. Varian is now Chief Economist for Google Inc. He was previously the Dean of the School of Information Management and Systems at the University of California at Berkeley. You can read a review of the book here. My approach is similar to that used by Shapiro and Varian, and some lectures lean heavily on their material. However, their book also has a lot of material on information technology which is not relevant to this course. There are also many topics in this course that are not covered by Shapiro and Varian. Bottom line - the book's not so expensive (about $20 new), so you should consider getting it if you think you will keep working in this field after you've finished this class. You would find this book helpful, but it's not required and you can certainly get by without it.
Online Reference Sources
You need to be able to do research for internet businesses, just like any other business. wikipedia is a great place to start, especially for technical information, but you should not use it as your ultimate source. You should use it to find sources.
The New York Times technology section is a user-friendly way to keep up with developments in internet business and technology. You can see headlines on the News Feed page. Fast Company is a business magazine that focuses on new businesses and has a lot of web-business related content.
Public companies are companies in which the general public can by shares. These shares are listed on Stock Exchanges like the New York Stock Exchange (NYSE) or NASDAQ.
Public companies are required by law to report to their shareholders. There are strict rules about the information they must disclose. These rules are administered by the Securities Exchange Commission (SEC) - so-called because shares and other financial instruments like bonds are called "financial securities". Public companies report quarterly and produce a detailed Annual report once a year. These reports are great sources of information about a company's finances.