There seems to be a heck of a lot of options these days so I figured I'd crowd source some geek zone experience/recommendations for this one.

We need to do a one off remote sales presentation over the internets, won't be a regular thing hence looking for something cheap or free.

The deskstop/screen being shared will be a web based application probably in Google Chrome or Firefox on either Mac OS or Windows (we have total control of this end).

There will probably be a couple of clients connecting from most likely Wellington, we are in Auckland and have a 100Mbit fibre connection at work, so no issues with bandwidth/connection speeds etc.  

Clients will have unknown OS at this stage (probabaly Mac OSX and Windows XP or 7 though).

Voice and chat don't necessarily need to be included in the software as we can use regular phone conference, but client end chat or annotation capability might be useful. We can annotate on top of the browser window at our end with web browser plugin though so not a biggie.

The idea solution will have minimal install requirements for the client end, one click install enter access code sort of thing.

Hit me with your recommendations and save me testing out a million different options, go team!