Alternatives to textbooks.

Sorry, I don't know of any interactive ones in real time.
Video archives of Q/A sessions exist for many contemporary celebrity researchers.

Thank you very much Fresco.
Do you think, in certain circumstances it could be a valuable tool? I'm sure there are certain scientific analyses that would benefit from it... charts that move etc.
My notion of it being pertinent to music was that it would be possible to portray a good number of things at the same time...

I taught for the Open University some time ago and I think they have multimedia presentations down to a fine art. I pretty sure I've seen analysis of musical scores using animated highlighting. Try looking them up.

As far as maths and physics are concerned there are quite a few websites where you can "play" with parameters and see what happens. e.g http://www.chaospro.de/

In the world of music, a lot of music appreciation textbooks now have interactive online components. You click on a sound clip and as you're listening, important information will pop up at specific moments. (It's pretty rudimentary stuff for a musician, of course.)

I don't know of any scholarly sources in musicology that do anything comparable, though I'm sure they're out there. I'd wager a guess that you'd sooner find it in music theory and analysis than in historical musicology. (Musicologists in general are always a few years behind the times anyway!)

Alex Ross is not considered a scholar per se, but his book The Rest is Noise, which is reasonably respected among the scholarly community, is designed to be read alongside audio clips found on his blog. It's a start, I guess.

More generally, a lot of textbook publishers are offering e-book versions of their texts and in some cases getting rid of the print versions of their texts altogether. Many of these e-books involve interactive features. As a way of keeping up with this, many colleges and universities (such as mine, for example) are starting to make Kindles, Nooks, and iPads more available to students. I know of at least three schools where certain courses included free iPads to students for the duration of the semester.

Thank you very much.
I was just thinking about whether an interactive website would be a better way to display analysis of musical multimedia- I was reading Nick Cook's chapter on Opera in analysing musical multimedia and kept having to flick back between graphs and screen shots and stuff and with a website you could by-pass it all... video clips could be inbuilt into the structure of the essay, and there could be more than one form of organisation.