The toss should be at least as high as the preferred contact point. That would be one extreme, but one that has been used by some of the best servers in history. Higher tosses allow you more time to get into position, but require more tossing skill on the part of the server.
How far you toss into the court is going to depend on your athleticism. The more powerfully you can jump into the serve, the more into the court you should toss. I'd suggest shooting for about a foot inside the court when you are first learning.