1 to 1 AND 1 to many video chat – advice

Hi all.
I’m after some advice on setting up a ‘1 to 1’ and ‘1 to many’ video chat website using wordpress and which plugins are best for this.

To give you the run down – I’m a tutor and would like to provide online tutoring to my students. At both one on one (most important) and classroom like.
I’m fairly experienced with wordpress but am not so experienced with any video chat stuff.

Ideally how i would like this to work – I use my laptop’s web camera, i provide my students a username and password (wordpress account), they login and see my web cam, i see theirs etc. We would also have a text chat window incase the students are sitting in library or such where noise is an issue. A way for the students to create their own accounts would be a bonus but not necessary.
Can anyone recommend a good free or very cheap plugin to do this and some recommendations on how to set it up?
Anyone done anything similar?
Thanks
Felix.