Remote talks

Hi folks

I may have someone who would like to talk at PHP Hampshire, but due to the
world being a little on the large side, it is cost prohibitive for them to
come in person, but the suggestion of doing a remote talk has been raised
(e.g. via Skype, Hangouts).

Unfortunately, I have virtually no experience of this sort of thing, and
although it wasn't over the WAN, the two-room keynote at PHPNW13 showed me
this sort of thing is possible... But I'm a novice at this, so if anyone is
able to help answering any/all of my questions, it'd be much appreciated!

Does anyone have any experience with this & can share the pros/cons of
this? What technology would work well? How would the slides work? How can
you get the slides and video feed at the same time? What's the best for
video feed? What's the best way of doing this? I can use Windows or Ubuntu
for this, and we do have a projector.

Thanks folks
James