Avid readers have long swapped books with friends. Now, with online book-swapping sites acting as middlemen, we can trade books with complete strangers. Although the basic concept is the same, each of the following sites handles the mechanics of postage and mailing labels slightly differently. Take a look at Bookins, and Paperback Swap. For more choices, here’s a longer list of book, CD and DVD swapping sites .

As the holidays approach, Internet shopping scams are on the rise. One simple thing you can do to protect yourself is to upgrade your browser to the newest version. Firefox now blocks sites that are known for phishing scams. Internet Explorer warns against suspicious activity even before sites are added to a blacklist. For more online holiday security tips, read PC World .

With the advent of waterproof MP3 players, diehard music fans can take their tunes into the water. Solutions range from waterproof cases for existing players to players designed especially for underwater use. For even more choices, browse Froogle.

For geeks that love high-tech gadgets, here are a few must read sites. Woot! is known for great pricing, but only sells one item per day. Head over early, because the best toys sell out quickly. For personal technology reviews, try Engadget, Gizmodo or Walt Mossberg of the Wall Street Journal.

Students, schools, and teachers often qualify for significant education discounts on popular software programs. Microsoft explains their academic discount program here. Two online stores that offer educational discounts are JourneyEd and Creation Engine.

Joel Mokyr, professor of economics and history at Northwestern University, compares the importance of Amazon.com’s new Search Inside the Book capability with the invention of the encyclopedia. To search the contents of 120,000 books, simply enter a phrase into Amazon’s regular search box. For more details on how this works, see Amazon’s help page.

There should be corollary to Murphy’s Law (”If anything can go wrong, it will”) that states “If anything goes wrong, you won’t be able to find the product manual.” But help is just a few clicks away. Live Manuals and Amazon.com both offer free user manuals for many manufacturers. And, last but not least, many manufacturers provide manuals at their websites.

For techies on the move with high-tech gadgets, battery life can be a major source of frustration. To learn more about choosing the right batteries visit these three sites: TechTV Battle of the Batteries Redux, Choosing Batteries and Chargers and How to Choose the Very Best Battery.