I am in the middle of writing a book and I am wondering:
Is there a place where I can send it and they say if it is good enough to publish?

Any of the places that you pay for the publishing will tell you it is good enough.

The thing is that there is not one place to send it, what type of book, fiction, history, love story, religious, sci fi, each may have its own pubishing company that works more in that field.

Each has its own rules as to what you can submit and what format it has to be in

Are you in school? A teacher or professor would be a good place to start.

You need to find a literary agent. You can find lists of them on the internet or in the library. Send a introduction letter asking if they are accepting manuscripts and tell them about yourself, your genre and your work.

I just went to a lecture by Diana Gabaldon last night and that is what she recommended.

Go to a writer's conference. At most of them, for a fee you can submit the first 30 pages of a manuscript for professional evaluation. Check Writer's Digest, The Writer and other magazines like that in the library or bookstore. They usually have a list of upcoming conferences.

Also- join a writer's group or organization. Most of them have monthly workshops which can help you. Join a writer's critique group. You can get a feel by listening to the comments of other writers.