Childwelfare.gov is an important resource. It lists all of the laws, state by state, that are pertinent to adoption, especially for expectant parents considering relinquishment. It is vitally important that you know the laws. For example, in my state and all but 16 (14?), open adoptions are not legally binding and can thus be closed by the adoptive family at any time without reason or warning. That is important to know about your own state. If you have problems traveling that site and finding information that you need, please don't hesitate to ask. I'm well versed in it now since I didn't have it as a resource when I was placing.
Furthermore, in addition to the stuff you've already been told, I encourage you to hit the "pavement," and seek out blogs by birth parents. Some are happy, some are NOT so happy but reading ALL sides of the story will help you better understand the grief and loss, happiness, longing, and hard work that are associated with adoptions, placement, openness and everything else involved.
If you have questions, please don't hesitate to ask.