Video Conferencing

Google+ Hangouts

Tutor/Study/Brainstorm/Practice... sessions with Google+ Hangouts.

Hangouts allows multiple participants to share video, audio, chat and screen sharing. Third party apps allow more functionality such as Cacoo (whiteboard, diagrams), Google Drive (document sharing), Slideshare (presentations), and Symphonica (task management).

Recording a Hangout is easy with Hangout On Air. This is broadcast for others to see and is saved to your YouTube account for viewing later. This can be helpful for study group sessions.

All you need is a Google account and you are ready to go.

Good examples of tutoring sessions can be seen at the Rochester Institute of Technology site.

Skype

Skype is a free and very useful video conference tool. There is no built in recording mechanism however and it's not easy to make use of other tools such as whiteboards and document sharing.

More

A quick search will reveal many video conferencing options, both free and fee based, as well as web and application based. Check out Vyew and iVisit.