Note: The internet provides sites with thousands of classes and lectures on every topic and subject dealing with genealogical research that a person could ever think of. The four sites below are exceptional in providing descriptions and links to a very impressive amount of sites providing lectures and classes.
Family Search offers over 1,600 beginners classes covering every topic, every country, every ethnicity and every time period for free on their web site. This is an unbelievably valuable resource for both the beginner and experienced genealogist. Most of these are small classes that take very little time to go through. They are filled with a lot of information and links to records and more information. To investigate and take advantage of these offerings you can go here.
Genealogy.com offers a wide variety of classes for free online covering some very interesting topics. The 50 classes offered can be found at this location.
Cyndi's List is a genealogical web site that has been around for a long time and is now days often overlooked. They have an impressive page with descriptions and links to 69 major providers of genealogical classes, some free and same paid. The page can be found here.
Youtube.com is one of the best sites for viewing free webinars and classes on every topic imaginable for genealogical research. Most run 20 minutes to an hour long and tend to be very well done. Youtube can be reached here.