Voice-over-Browser technologies? Allow 2 people to speak via webpage?

I am one of the founding members of a startup company that will offer online expert reviews for a particular field.

Part of the core functionality of our site will involve connecting the client with a reviewer using live audio so they can speak with each other during the review. I’d really like to find a way to do this from within the browser, rather than having to rely on locally installed software to be able to pull this off (such as Skype, iChat, etc.).

Can it be done using Flash? Isn’t this basically how chatroulette.com works (without the video… just audio)? Is it expensive or somehow problematic to try pulling this off via Flash? Can someone point me in the right direction that I can steer my web developer toward for learning more about accomplishing this via Flash?

Are there any other browser based methods of going about accomplishing this, through the use of plugins, applets, or other browser based tools (i.e. java, etc, etc.) that I should consider if trying to pull something like this off?

Any links to API’s or product pages for such tools, and any other suggestions would be greatly appreciated… Thanks!

You would need this for Flash to have voice-chat: media server for streaming video | Adobe Flash Media Server family
So yes it can be expensive and well rather poor. You would be better off just using Skype or a similar product.
Sorry to say, but I doubt you’ll have anything as user-friendly as Skype. Or as cheap.

There’s probably some existing API’s or services out there. Google Voice, maybe?