Okay, first off, it is illegal to possess wild bird eggs of any sort without proper permits, and secondly, there is an enormous amount of work that goes into raising a baby owl. I know everybody gets those fuzzy feelings when they think of how cool it would be to hatch a "Harry Potter" bird, but unless you have permits and a great deal of education and commitment to go along with those fuzzy feelings, you need to back away from the eggs and not even think about incubating them. It's very hard for some to let common sense prevail over the initial "Awwww!" response, I know, but it's very important to know your limits and do what's right.
Sorry if I'm too blunt, but there were way too many, "Go for it and hatch it!" posts on here for comfort. This is not like hatching a chicken, and shouldn't be treated so lightly.