By homeschooling your children, you will provide them with the opportunity to progress at their own pace, to pursue their own interests, and discover their hidden talents at a young age. Instead of following a curriculum established by someone who does not know your children or their learning styles, you can observe your children's progress, and plan your studies and activities accordingly.
Sending them to school will not "make them smart" they already are smart! They will memorize page upon page of information, facts, and dates. But is memorizing data to pass the test on Friday then forgetting it by Monday true learning? Homeschooling will allow them to spend two months on a subject that interests them not just 45 minutes of class time. They will be truly learning in freedom.
The same general advice really applies to all children. Provide an intellectually stimulating environment, read a lot together, and allow the twins the opportunity to pursue their interests. You'll be amazed at what will unfold.