Tuyet, my research is very old. I was totally taken with the boards back in 1998. I wrote my doctoral dissertation about the use with 8th grade writing students. I do have some data still up. Try this link: http://www.shsu.edu/~lis_mah/documents/whywhiteboards.htm
Then there is an article, not much newer: http://teachers.net/gazette/JAN02/mabell.html
Actually I think the things I say there are still true. But I regret that I have not followed up with more recent research. I guess my dissertation is still out there via UMI or something, but it was published 2000. Good luck with your work. I still believe the boards are super tools, especially if the kids are at the board instead of a lecturer or teacher hogging it.
With your interest in Online Interactive White Boards, I recommend you take a look at Wiziq's virtual classroom and authorstream's power point presentation platform. Both are web based platforms, have a bunch of features and free basic service.
Here’s a Public Class on Technology Integration you might be interested in.