I know that maybe your question has been answered for you, however, I thought I would just add my 2 cents.
It's prudent of you to be thinking about this now. In fact the best time to take action is when you are healthy.
Having a will is simply not enough. What will happen to your children if you are not dead? What if you are so incapcitated you are unable to take care of your children? what if you will need care? If you are incapcitated, would you want the doctors to try all means to revive you or would you rather DNR (do not resucitate)? What about property, businesses or other assets that you have?
I strongly recommend that you seek the advice of a good estate planner/trust attorney. Although do-it-yourself kits are available out there, I have heard that sometimes those documents may do more harm than good.
I hope this helps! And also, kudos to you for thinking of your children's well being now!