Hey Scorpianflower - Welcome!
As far as agencies go, private message (PM) Brenda Romanchik here:
Adoption.com Forums - MyPage: bromanchik She is an adoption councilor and will point you to an ethical agency in your area. I personally don't recommend attorneys but that's just my scotoma. Agencies offer counseling support which can be very helpful post-adoption.
Try not to rule out Open Adoption before you have learned more. Having some contact throughout your child’s life has shown to be quite healthy for the child and certainly knowing that they are adopted is best. Most figure it out anyway - hiding the fact just makes it feel like a lie. Check out some of the adoptee boards here and/or post a question. They will give you the adopted person’s perspective.
Take care of yourself... Stay here, learn and lean on us when you need to - this is a great place to find support.