I love teaching via Skype! I guess teaching beginners would be harder but I don't really teach any so I can't comment.
The good things for you...
-You can pretty much reach anyone on the globe as long as there connection is up to speed (you can check this with them before the lesson). This means your potential client list is LARGE!
-You get to connect with people from completely different backgrounds and cultures... I've given lessons to people from the Dominican Republic, Barbados, Italy, France, Australia, Malaysia etc etc. And I live in the UK.
The good points for them...
-They can actually get a great teacher and not have to put up with the guitar teacher at the local music store who happens to play a little bit of bass.
-If they are quite advanced they can choose a tutor that specializes in what they want to focus on. For example... if someone wants to learn how to slap like Victor Wooten i'm not your guy, but on the other hand if you they wanna learn how to play over giant steps in 7/8 i'm your man lol!
Basically it just gives them more options.
The bad bits...
-Depending where they are the connection can be bad... but you should check this out before hand.
-The 'scare factor'. Giving Skype lessons can be quite weird to start with, especially to new students... You click a button and then suddenly there's a guy in front of you that you've never met before with a bass in his hands. I was nervous to start with but you soon get used to it. The gag is... prepare the lessons before hand!!! Have at least 15 different areas you can touch on within a lesson, each with different exercises. Obviously you don't want to touch on each of these different areas in one lesson... i try to do around two different concepts per lesson. But, it helps to have them on hand if you need them.
Hope that helps man. I really believe this is going to be the way everything goes in the future so hop on the wagon man!
Gimme a shout if you need any other pointers.
Scott. Scottsbasslessons SCOTT DEVINE-BASS PLAYER-COMPOSER-EDUCATOR