join.me is an easy to use screen sharing site. To share your screen with others, you download their executable file and away you go. It is very simple to set up and use. After you run the executable file, it sets up the toolbar above at the top of your screen. You share the code via email or people can go to join.me and enter the code to join up. The code is unique for each sharing session.
The free version includes screen sharing, chat, file transfer, and remote control abilities. There is also a pro version that adds some more features. You can also hold a phone conference.
I recently used join.me to share my screen with my students as I showed them how to do some things in Google Docs.
This is great for conducting distance training, professional development, and working with your students.