As someone who also teaches Internet classes... you might also want to cover a little about knowing when a site is legit. If they are paying a lot of money for their holiday, how do they know that the site is secure, registered with IATA, and so on?

How to evaluate reviews and ratings for themselves: eg many great places get terrible reviews on Trip Advisor because someone didn't like the carpet and rated it poorly. Teach them to learn how to look at a few sites and compare. I also like hostelworld.com - not just hostels, also covers budget hotels especially in Europe.

Also cover forums - eg I like Lonely Planet's Thorntree http://thorntree.lonelyplanet.com for general questions about where to go and what to do.

Lastly - a couple of insurance sites, but be sure to point them to the conditions.