I've been looking for this myself, in fact i posted a similar question having not read your post :o
I have found that hemscott offer this for UK companies, although as far as i know it doesn't show dates for other companies in the sector. However you can see upcoming announcements for all...
Hi All
Does anyone know of a site that lists upcoming corporate announcements (interims, finals etc) for the forthcoming month ideally with estimates?
Many Thanks!
Toby