Hi,
Uh, really? I was going to use it in a letter... I have to write an email to the Munich turist office... Should I say: "Dear German office workers..."? LOL
So I was thinking of using "To whom it may concern".
Email is much more informal than 'regular' mail. You don't usually need any salutation at all. Just use politeness.
eg Just say simply
I would be very grateful if you could send me some information about hotels and tourist attractions in Munich.
Thank you
Best wishes, Clive