Most libraries have a digital card catalogue so it is obviously the job of the media specialist to help users learn how to use it effectively. Some online card catalogues include the option for saving references and creating biographies.
While I think using one of the online portals (see Integrator/Content) is probably better than starting with a search engine, we should help students learn about appropriate search techniques. Luckily, search engines usually offer help, and since it varies from one engine to another, you might want to choose one or two as your in-house engines and then educate students and teachers how to use them. Here are the advanced search techniques for Google.
The place to go to learn everything you ever wanted to know about search engines is Search Engine Watch.
Here's a great series of tutorials on doing research.