Yes, You can teach online with a TEFL Certificate. There are many online companies to start teaching with and more are appearing each day. Have a look at our resources page form some Online Teaching Companies.
My Educational Qualifications include a Master of Arts in Applied Linguistics and TESOL, Post Graduate Certificate in Education, TEFL Trainer Certified and a TEFL Certificate. On top of that I have 10+ Years TEFL experience in Asia and Europe, teaching students of all ages and backgrounds.