For those preparing for auditions, check out the Berlin International Music Festival which will be held this summer from July 19 - August 8.
I've worked with some of the people running the program and they are very good. They have been involved in all aspects of the european opera business and have lots of good pointers. Instruction will be in English and in German.
There is also a competition for Singers and Pianists at the end of the master classes. Check out their website!
http://www.berlininternationalmusicfestival.de/