Voki allows you to create speaking avatars and use them on websites and in email messages.
(Click on the image above).
This is popular with many MFL teachers.
There is a Voki for Education blog which includes suggestions for educational use.
Note that using a Wiki could be used to provide a way for a class to upload a series of Vokis as they can be embedded easily on a wiki pages.
See this Wikispaces page for an example.
Russell Stannard has created these very clear training videos on Voki.
The National Centre for languages has provided two tutorials, one on creating your avatar, the second on recording a voki.