Stoodle provides an online interactive whiteboard environment in which to conduct lessons.
E-Safety note: For your own safety and that of your students, it’s wise to avoid being in an environment like this alone with your class. Much better for colleagues to team-up.
Imagine you want to present a series of photos or slides, but your audience is elsewhere – a colleague/class in another school, perhaps around the world! livepics.io will let you do that, simply and with the minimum of fuss.
Tough to explain all the capabilities of the online recording and podcasting tool that is Evoca in just 3 minutes. However for language teachers (and others?) and with the capability to record from a phone, Skype or a computer, this is well worth looking at in more detail.
If you need videoconferencing in a hurry, without the need to set up an account, then meetingl might suit your needs.
Yugma is a webconferencing tool which offers desktop sharing and can be usefully employed to provide remote tutorials to students.
Wiggio brings together in a single application an extensive toolset to make working with a group of people so much easier. Incredibly useful if you’re not co-located, or even just have difficulty getting together synchronously.
When you can’t be in the same place as your students/colleagues, but want to meet, you need an online collaborative environment like ShowDocument.