There are a number of websites that give more information about Mr. David Miscavige.
As the Chairman of the Board Relgious Technology Center, he has often addressed Scientologists at events. This has been at celebrations of L. Ron Hubbard's birthday, at the openings of new Churches and other major events marking the expansion of the Scientology religion.
There are various profiles on Mr. Miscavige and some relevant links are here:
NNDB People
Various interesting postings
Official Press Page
Blogs by others of interest
Covering humanitarian activities