Hi!

I plan to conduct some lectures for my students located at different location and i need a webinar type solution for linux (and specifically ubuntu coz i happen to use it).

I need the following features:
> Audio Support, so students can hear my voice.
> Screensharing support, so i can play presentations and show them how to really do it.
> Chat, so they can ask questions.
> And Free

Currenlt i have 12 people, later if i get more i might buy one.

I tried dimdim but neither screensharing nor audio worked. What do you suggest?

Also my local system is not on a static ip, so vnc sorrta thing isn't possible, i guess...

I am not so sure that the vnc thing wont work for you. A dynamic ip only means that every time you want them to be able to connect to you you have to provide them with the current ip.

Take a look at http://www.karlrunge.com/x11vnc/ it allows you to share the actual desktop you are using most others don't.

If you through Ultra-vnc into the mix you should be able to get instant chat going.

I can't help with the sound thing.