No, it IS an instant messenger type of thing.
Except you can call people, at no cost if I recall correctly, this is what we used to call Badspot's parents.. uh oops, I mean.. well, I didn't call them anyway, some other guy did, and that same guy called me also.
Ventrilo is for use with more people, like a group all at once, and is more useful than Skype at times.