How to Come out to your Children
First, ask yourself how comfortable you are with your own lesbianism. Practice on a friend. Your confidence will be conveyed and your child will feel more comfortable.

Choose a good time and place. Pick a time when you will not be interrupted and you have time sit with them as long as they need.

Consider their age. Use appropriate language for their development. For young children, don’t give too much information.

“I love Patty like Uncle Tom loves Aunt Karen.” Let them know that some people will think it is wrong for two girls to love each other, but that you and your friends do not think it is wrong.

Remember that if their initial reaction is negative, that they may come around. Try to provide outside support like a group for teens with gay parents. Your local PFLAG chapter is a good place to start. Also, many high schools now have Gay/Straight Alliances, which can be a great place for children of gay parents to fit in.

Let them know you are the same person, you are still their mom and you will be treating them the same way you always have. Explain that you just want them to know this important information about you.

Keep talking. Coming out is a process. Let them know they can ask questions.

Additional Resources:
PFLAG
The Lesbian Parenting Book