There seem to be some problems with Google Apps since approximately 11:00 CET on 24th of februari 2009. When you are trying to login, you'll get an error like this:
The server encountered a temporary error and could not complete your request.
Please try again in 30 seconds.
The title bar reads:
502 Server Error
The issue is discussed in The Google support forum. Meanwhile, we will wait for Google Apps to be available again...