ventrilo or any other alternative

[Mohammed Al-shar']

dear listers.

hi, finally my new linux box is working fine except for the audio issue, but 
that will be in another post. anyway, is it possible to install ventrilo or 
any other alternative voip client accessibly under ubuntu?

here's what i am thinking. I want to be able to provide our customers with 
remote training by voice, like give a class and have the audience ask 
questions. is this doable? do how can I do this best? nhote that my audience 
are mostly windows users, so the client side will have to have windows 
version.

thanks
Mohammed al-shar'