The Wrath beta realms are down as I type this. Not news, I know, for those who are actually in the beta. The realms seem to be unavailable frequently. I chalk this up to the nature of beta testing. However, today we actually got a heads-up on planned maintenance downtime, scheduled for tomorrow at the same time the live realms will be offline. Now, this is news to me because so far the patches to the beta have been released without any announcement. In other words, the only way I've found out updates were coming was that when I try to log on, and then I end up waiting an hour for everything to download and install.
UPDATED: According to the beta forums, the beta realms will be offline starting at 9:00AM Pacific time September 9th 2008 for one to two hours.