As you raise a child or begin teaching one, be sure to show them by example. Telling is good, but showing is better.
There are good and bad people in all walks of life, regardless of sex, color or religion, and the best way to protect and teach her this fact is to explain this to her. As she grows older she will already be comfortable with asking questions about the subject of homosexuality because you have been teaching her about differences in people all along.
In order for your child to be comfortable around gays, you have to be comfortable around them as well. If you know someone who is gay, talk to them openly about their lifestyle and ask questions. It may be uncomfortable at first but most people are more than happy to discuss this because they know it is how people learn to accept one another.
Realize that just because you accept a gay person's lifestyle it does not mean others will think you are gay. Homophobia is described as a fear of being gay or a fear of homosexuality being contagious. Homosexuality is not, by any means, contagious. You must be comfortable with yourself in order to be comfortable with others.
When asked questions about your feelings toward homosexuality be honest in your answers. But more importantly, listen to the responses. Don't let fear intrude on your logic and don't decide it's wrong just because it's something you don't agree with. You may not agree with it, but still realize it isn't your decision what others do. Just because you accept differences in others, it doesn't mean you have to like it or agree with it.
Children are more open-minded than adults due to adults having already formed opinions which are usually based on how they're raised. Remember this when talking to people about homosexuality and base your discussion appropriately.