The forms to receive US citizenship for your child
are available on the US embassy site. There is also a fairly detailed list of the things you will need, and answers to the most common questions.
Something that they do not seem to make clear is that you will NEED to do the application within 90 days of your child`s birth, or will be charged incredible fees and have a very very difficult time getting citizenship for your child.
If your child is born with complications preventing travel within the first 90 days (I very much hope that this does not happen!), expect to be unable to obtain citizenship. They will not make any exceptions for the "in person" rule, even if the child is in intensive care. (Happened to me, so I caution people on this.)